GNU Coreutils
From Gentoo Wiki
The coreutils package contains the GNU coreutils, which provide many of the basic commands of the UNIX(like) OS.
These commands are provided for quick reference only, with some Gentoo specific notes. For up to date and in depth documentation, see the local --help options and man pages for each command.
These commands are powerful, but beware that this means that data loss may be incurred in case of misuse. Always backup important data. Pay particular attention when working with escalated privileges.
Gentoo includes util-linux package in the @system set.
Installation
The coreutils package is part of the system set so it should not need installing.
Usage
Depending on the shell used, some of these commands may be pre-empted by shell builtins.
arch
Print machine hardware name (same as uname -m).
user $arch --helpUsage: arch [OPTION]...
Print machine architecture.
--help display this help and exit
--version output version information and exit
GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
Full documentation <https://www.gnu.org/software/coreutils/arch>
or available locally via: info '(coreutils) arch invocation'
b2sum
Compute and check BLAKE2 message digest.
user $b2sum --helpUsage: b2sum [OPTION]... [FILE]...
Print or check BLAKE2 (512-bit) checksums.
With no FILE, or when FILE is -, read standard input.
-b, --binary read in binary mode
-c, --check read BLAKE2 sums from the FILEs and check them
-l, --length digest length in bits; must not exceed the maximum for
the blake2 algorithm and must be a multiple of 8
--tag create a BSD-style checksum
-t, --text read in text mode (default)
-z, --zero end each output line with NUL, not newline,
and disable file name escaping
The following five options are useful only when verifying checksums:
--ignore-missing don't fail or report status for missing files
--quiet don't print OK for each successfully verified file
--status don't output anything, status code shows success
--strict exit non-zero for improperly formatted checksum lines
-w, --warn warn about improperly formatted checksum lines
--help display this help and exit
--version output version information and exit
The sums are computed as described in RFC 7693. When checking, the input
should be a former output of this program. The default mode is to print a
line with checksum, a space, a character indicating input mode ('*' for binary,
' ' for text or where binary is insignificant), and name for each FILE.
Note: There is no difference between binary mode and text mode on GNU systems.
GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
Full documentation <https://www.gnu.org/software/coreutils/b2sum>
or available locally via: info '(coreutils) b2sum invocation'
base32
Base32 encode/decode data and print to standard output.
user $base32 --helpUsage: base32 [OPTION]... [FILE]
Base32 encode or decode FILE, or standard input, to standard output.
With no FILE, or when FILE is -, read standard input.
Mandatory arguments to long options are mandatory for short options too.
-d, --decode decode data
-i, --ignore-garbage when decoding, ignore non-alphabet characters
-w, --wrap=COLS wrap encoded lines after COLS character (default 76).
Use 0 to disable line wrapping
--help display this help and exit
--version output version information and exit
The data are encoded as described for the base32 alphabet in RFC 4648.
When decoding, the input may contain newlines in addition to the bytes of
the formal base32 alphabet. Use --ignore-garbage to attempt to recover
from any other non-alphabet bytes in the encoded stream.
GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
Full documentation <https://www.gnu.org/software/coreutils/base32>
or available locally via: info '(coreutils) base32 invocation'
base64
Base64 encode/decode data and print to standard output.
user $base64 --helpUsage: base64 [OPTION]... [FILE]
Base64 encode or decode FILE, or standard input, to standard output.
With no FILE, or when FILE is -, read standard input.
Mandatory arguments to long options are mandatory for short options too.
-d, --decode decode data
-i, --ignore-garbage when decoding, ignore non-alphabet characters
-w, --wrap=COLS wrap encoded lines after COLS character (default 76).
Use 0 to disable line wrapping
--help display this help and exit
--version output version information and exit
The data are encoded as described for the base64 alphabet in RFC 4648.
When decoding, the input may contain newlines in addition to the bytes of
the formal base64 alphabet. Use --ignore-garbage to attempt to recover
from any other non-alphabet bytes in the encoded stream.
GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
Full documentation <https://www.gnu.org/software/coreutils/base64>
or available locally via: info '(coreutils) base64 invocation'
basename
Strip directory and suffix from filenames.
user $basename --helpUsage: basename NAME [SUFFIX]
or: basename OPTION... NAME...
Print NAME with any leading directory components removed.
If specified, also remove a trailing SUFFIX.
Mandatory arguments to long options are mandatory for short options too.
-a, --multiple support multiple arguments and treat each as a NAME
-s, --suffix=SUFFIX remove a trailing SUFFIX; implies -a
-z, --zero end each output line with NUL, not newline
--help display this help and exit
--version output version information and exit
Examples:
basename /usr/bin/sort -> "sort"
basename include/stdio.h .h -> "stdio"
basename -s .h include/stdio.h -> "stdio"
basename -a any/str1 any/str2 -> "str1" followed by "str2"
GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
Full documentation <https://www.gnu.org/software/coreutils/basename>
or available locally via: info '(coreutils) basename invocation'
basenc
Encode/decode data and print to standard output.
user $basenc --helpUsage: basenc [OPTION]... [FILE]
basenc encode or decode FILE, or standard input, to standard output.
With no FILE, or when FILE is -, read standard input.
Mandatory arguments to long options are mandatory for short options too.
--base64 same as 'base64' program (RFC4648 section 4)
--base64url file- and url-safe base64 (RFC4648 section 5)
--base32 same as 'base32' program (RFC4648 section 6)
--base32hex extended hex alphabet base32 (RFC4648 section 7)
--base16 hex encoding (RFC4648 section 8)
--base2msbf bit string with most significant bit (msb) first
--base2lsbf bit string with least significant bit (lsb) first
-d, --decode decode data
-i, --ignore-garbage when decoding, ignore non-alphabet characters
-w, --wrap=COLS wrap encoded lines after COLS character (default 76).
Use 0 to disable line wrapping
--z85 ascii85-like encoding (ZeroMQ spec:32/Z85);
when encoding, input length must be a multiple of 4;
when decoding, input length must be a multiple of 5
--help display this help and exit
--version output version information and exit
When decoding, the input may contain newlines in addition to the bytes of
the formal alphabet. Use --ignore-garbage to attempt to recover
from any other non-alphabet bytes in the encoded stream.
GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
Full documentation <https://www.gnu.org/software/coreutils/basenc>
or available locally via: info '(coreutils) basenc invocation'
cat
Concatenate files and print on the standard output.
user $cat --helpUsage: cat [OPTION]... [FILE]...
Concatenate FILE(s) to standard output.
With no FILE, or when FILE is -, read standard input.
-A, --show-all equivalent to -vET
-b, --number-nonblank number nonempty output lines, overrides -n
-e equivalent to -vE
-E, --show-ends display $ at end of each line
-n, --number number all output lines
-s, --squeeze-blank suppress repeated empty output lines
-t equivalent to -vT
-T, --show-tabs display TAB characters as ^I
-u (ignored)
-v, --show-nonprinting use ^ and M- notation, except for LFD and TAB
--help display this help and exit
--version output version information and exit
Examples:
cat f - g Output f's contents, then standard input, then g's contents.
cat Copy standard input to standard output.
GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
Full documentation <https://www.gnu.org/software/coreutils/cat>
or available locally via: info '(coreutils) cat invocation'
chcon
Change file security context.
user $chcon --helpUsage: chcon [OPTION]... CONTEXT FILE...
or: chcon [OPTION]... [-u USER] [-r ROLE] [-l RANGE] [-t TYPE] FILE...
or: chcon [OPTION]... --reference=RFILE FILE...
Change the SELinux security context of each FILE to CONTEXT.
With --reference, change the security context of each FILE to that of RFILE.
Mandatory arguments to long options are mandatory for short options too.
--dereference affect the referent of each symbolic link (this is
the default), rather than the symbolic link itself
-h, --no-dereference affect symbolic links instead of any referenced file
-u, --user=USER set user USER in the target security context
-r, --role=ROLE set role ROLE in the target security context
-t, --type=TYPE set type TYPE in the target security context
-l, --range=RANGE set range RANGE in the target security context
--no-preserve-root do not treat '/' specially (the default)
--preserve-root fail to operate recursively on '/'
--reference=RFILE use RFILE's security context rather than specifying
a CONTEXT value
-R, --recursive operate on files and directories recursively
-v, --verbose output a diagnostic for every file processed
The following options modify how a hierarchy is traversed when the -R
option is also specified. If more than one is specified, only the final
one takes effect.
-H if a command line argument is a symbolic link
to a directory, traverse it
-L traverse every symbolic link to a directory
encountered
-P do not traverse any symbolic links (default)
--help display this help and exit
--version output version information and exit
GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
Full documentation <https://www.gnu.org/software/coreutils/chcon>
or available locally via: info '(coreutils) chcon invocation'
chgrp
Change group ownership.
user $chgrp --helpUsage: chgrp [OPTION]... GROUP FILE...
or: chgrp [OPTION]... --reference=RFILE FILE...
Change the group of each FILE to GROUP.
With --reference, change the group of each FILE to that of RFILE.
-c, --changes like verbose but report only when a change is made
-f, --silent, --quiet suppress most error messages
-v, --verbose output a diagnostic for every file processed
--dereference affect the referent of each symbolic link (this is
the default), rather than the symbolic link itself
-h, --no-dereference affect symbolic links instead of any referenced file
(useful only on systems that can change the
ownership of a symlink)
--no-preserve-root do not treat '/' specially (the default)
--preserve-root fail to operate recursively on '/'
--reference=RFILE use RFILE's group rather than specifying a
GROUP value
-R, --recursive operate on files and directories recursively
The following options modify how a hierarchy is traversed when the -R
option is also specified. If more than one is specified, only the final
one takes effect.
-H if a command line argument is a symbolic link
to a directory, traverse it
-L traverse every symbolic link to a directory
encountered
-P do not traverse any symbolic links (default)
--help display this help and exit
--version output version information and exit
Examples:
chgrp staff /u Change the group of /u to "staff".
chgrp -hR staff /u Change the group of /u and subfiles to "staff".
GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
Full documentation <https://www.gnu.org/software/coreutils/chgrp>
or available locally via: info '(coreutils) chgrp invocation'
chmod
Change file mode bits.
user $chmod --helpUsage: chmod [OPTION]... MODE[,MODE]... FILE...
or: chmod [OPTION]... OCTAL-MODE FILE...
or: chmod [OPTION]... --reference=RFILE FILE...
Change the mode of each FILE to MODE.
With --reference, change the mode of each FILE to that of RFILE.
-c, --changes like verbose but report only when a change is made
-f, --silent, --quiet suppress most error messages
-v, --verbose output a diagnostic for every file processed
--no-preserve-root do not treat '/' specially (the default)
--preserve-root fail to operate recursively on '/'
--reference=RFILE use RFILE's mode instead of MODE values
-R, --recursive change files and directories recursively
--help display this help and exit
--version output version information and exit
Each MODE is of the form '[ugoa]*([-+=]([rwxXst]*|[ugo]))+|[-+=][0-7]+'.
GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
Full documentation <https://www.gnu.org/software/coreutils/chmod>
or available locally via: info '(coreutils) chmod invocation'
chown
Change file owner and group.
user $chown --helpUsage: chown [OPTION]... [OWNER][:[GROUP]] FILE...
or: chown [OPTION]... --reference=RFILE FILE...
Change the owner and/or group of each FILE to OWNER and/or GROUP.
With --reference, change the owner and group of each FILE to those of RFILE.
-c, --changes like verbose but report only when a change is made
-f, --silent, --quiet suppress most error messages
-v, --verbose output a diagnostic for every file processed
--dereference affect the referent of each symbolic link (this is
the default), rather than the symbolic link itself
-h, --no-dereference affect symbolic links instead of any referenced file
(useful only on systems that can change the
ownership of a symlink)
--from=CURRENT_OWNER:CURRENT_GROUP
change the owner and/or group of each file only if
its current owner and/or group match those specified
here. Either may be omitted, in which case a match
is not required for the omitted attribute
--no-preserve-root do not treat '/' specially (the default)
--preserve-root fail to operate recursively on '/'
--reference=RFILE use RFILE's owner and group rather than
specifying OWNER:GROUP values
-R, --recursive operate on files and directories recursively
The following options modify how a hierarchy is traversed when the -R
option is also specified. If more than one is specified, only the final
one takes effect.
-H if a command line argument is a symbolic link
to a directory, traverse it
-L traverse every symbolic link to a directory
encountered
-P do not traverse any symbolic links (default)
--help display this help and exit
--version output version information and exit
Owner is unchanged if missing. Group is unchanged if missing, but changed
to login group if implied by a ':' following a symbolic OWNER.
OWNER and GROUP may be numeric as well as symbolic.
Examples:
chown root /u Change the owner of /u to "root".
chown root:staff /u Likewise, but also change its group to "staff".
chown -hR root /u Change the owner of /u and subfiles to "root".
GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
Full documentation <https://www.gnu.org/software/coreutils/chown>
or available locally via: info '(coreutils) chown invocation'
chroot
Run command or interactive shell with special root directory.
user $chroot --helpUsage: chroot [OPTION] NEWROOT [COMMAND [ARG]...]
or: chroot OPTION
Run COMMAND with root directory set to NEWROOT.
--groups=G_LIST specify supplementary groups as g1,g2,..,gN
--userspec=USER:GROUP specify user and group (ID or name) to use
--skip-chdir do not change working directory to '/'
--help display this help and exit
--version output version information and exit
If no command is given, run '"$SHELL" -i' (default: '/bin/sh -i').
GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
Full documentation <https://www.gnu.org/software/coreutils/chroot>
or available locally via: info '(coreutils) chroot invocation'
cksum
Checksum and count the bytes in a file.
user $cksum --helpUsage: cksum [FILE]...
or: cksum [OPTION]
Print CRC checksum and byte counts of each FILE.
--help display this help and exit
--version output version information and exit
GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
Full documentation <https://www.gnu.org/software/coreutils/cksum>
or available locally via: info '(coreutils) cksum invocation'
comm
Compare two sorted files line by line.
user $comm --helpUsage: comm [OPTION]... FILE1 FILE2
Compare sorted files FILE1 and FILE2 line by line.
When FILE1 or FILE2 (not both) is -, read standard input.
With no options, produce three-column output. Column one contains
lines unique to FILE1, column two contains lines unique to FILE2,
and column three contains lines common to both files.
-1 suppress column 1 (lines unique to FILE1)
-2 suppress column 2 (lines unique to FILE2)
-3 suppress column 3 (lines that appear in both files)
--check-order check that the input is correctly sorted, even
if all input lines are pairable
--nocheck-order do not check that the input is correctly sorted
--output-delimiter=STR separate columns with STR
--total output a summary
-z, --zero-terminated line delimiter is NUL, not newline
--help display this help and exit
--version output version information and exit
Note, comparisons honor the rules specified by 'LC_COLLATE'.
Examples:
comm -12 file1 file2 Print only lines present in both file1 and file2.
comm -3 file1 file2 Print lines in file1 not in file2, and vice versa.
GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
Full documentation <https://www.gnu.org/software/coreutils/comm>
or available locally via: info '(coreutils) comm invocation'
cp
Copy files and directories.
user $cp --helpUsage: cp [OPTION]... [-T] SOURCE DEST
or: cp [OPTION]... SOURCE... DIRECTORY
or: cp [OPTION]... -t DIRECTORY SOURCE...
Copy SOURCE to DEST, or multiple SOURCE(s) to DIRECTORY.
Mandatory arguments to long options are mandatory for short options too.
-a, --archive same as -dR --preserve=all
--attributes-only don't copy the file data, just the attributes
--backup[=CONTROL] make a backup of each existing destination file
-b like --backup but does not accept an argument
--copy-contents copy contents of special files when recursive
-d same as --no-dereference --preserve=links
-f, --force if an existing destination file cannot be
opened, remove it and try again (this option
is ignored when the -n option is also used)
-i, --interactive prompt before overwrite (overrides a previous -n
option)
-H follow command-line symbolic links in SOURCE
-l, --link hard link files instead of copying
-L, --dereference always follow symbolic links in SOURCE
-n, --no-clobber do not overwrite an existing file (overrides
a previous -i option)
-P, --no-dereference never follow symbolic links in SOURCE
-p same as --preserve=mode,ownership,timestamps
--preserve[=ATTR_LIST] preserve the specified attributes (default:
mode,ownership,timestamps), if possible
additional attributes: context, links, xattr,
all
--no-preserve=ATTR_LIST don't preserve the specified attributes
--parents use full source file name under DIRECTORY
-R, -r, --recursive copy directories recursively
--reflink[=WHEN] control clone/CoW copies. See below
--remove-destination remove each existing destination file before
attempting to open it (contrast with --force)
--sparse=WHEN control creation of sparse files. See below
--strip-trailing-slashes remove any trailing slashes from each SOURCE
argument
-s, --symbolic-link make symbolic links instead of copying
-S, --suffix=SUFFIX override the usual backup suffix
-t, --target-directory=DIRECTORY copy all SOURCE arguments into DIRECTORY
-T, --no-target-directory treat DEST as a normal file
-u, --update copy only when the SOURCE file is newer
than the destination file or when the
destination file is missing
-v, --verbose explain what is being done
-x, --one-file-system stay on this file system
-Z set SELinux security context of destination
file to default type
--context[=CTX] like -Z, or if CTX is specified then set the
SELinux or SMACK security context to CTX
--help display this help and exit
--version output version information and exit
By default, sparse SOURCE files are detected by a crude heuristic and the
corresponding DEST file is made sparse as well. That is the behavior
selected by --sparse=auto. Specify --sparse=always to create a sparse DEST
file whenever the SOURCE file contains a long enough sequence of zero bytes.
Use --sparse=never to inhibit creation of sparse files.
When --reflink[=always] is specified, perform a lightweight copy, where the
data blocks are copied only when modified. If this is not possible the copy
fails, or if --reflink=auto is specified, fall back to a standard copy.
Use --reflink=never to ensure a standard copy is performed.
The backup suffix is '~', unless set with --suffix or SIMPLE_BACKUP_SUFFIX.
The version control method may be selected via the --backup option or through
the VERSION_CONTROL environment variable. Here are the values:
none, off never make backups (even if --backup is given)
numbered, t make numbered backups
existing, nil numbered if numbered backups exist, simple otherwise
simple, never always make simple backups
As a special case, cp makes a backup of SOURCE when the force and backup
options are given and SOURCE and DEST are the same name for an existing,
regular file.
GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
Full documentation <https://www.gnu.org/software/coreutils/cp>
or available locally via: info '(coreutils) cp invocation'
csplit
Split a file into sections determined by context lines.
user $csplit --helpUsage: csplit [OPTION]... FILE PATTERN...
Output pieces of FILE separated by PATTERN(s) to files 'xx00', 'xx01', ...,
and output byte counts of each piece to standard output.
Read standard input if FILE is -
Mandatory arguments to long options are mandatory for short options too.
-b, --suffix-format=FORMAT use sprintf FORMAT instead of %02d
-f, --prefix=PREFIX use PREFIX instead of 'xx'
-k, --keep-files do not remove output files on errors
--suppress-matched suppress the lines matching PATTERN
-n, --digits=DIGITS use specified number of digits instead of 2
-s, --quiet, --silent do not print counts of output file sizes
-z, --elide-empty-files remove empty output files
--help display this help and exit
--version output version information and exit
Each PATTERN may be:
INTEGER copy up to but not including specified line number
/REGEXP/[OFFSET] copy up to but not including a matching line
%REGEXP%[OFFSET] skip to, but not including a matching line
{INTEGER} repeat the previous pattern specified number of times
{*} repeat the previous pattern as many times as possible
A line OFFSET is a required '+' or '-' followed by a positive integer.
GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
Full documentation <https://www.gnu.org/software/coreutils/csplit>
or available locally via: info '(coreutils) csplit invocation'
cut
Remove sections from each line of files.
user $cut --helpUsage: cut OPTION... [FILE]...
Print selected parts of lines from each FILE to standard output.
With no FILE, or when FILE is -, read standard input.
Mandatory arguments to long options are mandatory for short options too.
-b, --bytes=LIST select only these bytes
-c, --characters=LIST select only these characters
-d, --delimiter=DELIM use DELIM instead of TAB for field delimiter
-f, --fields=LIST select only these fields; also print any line
that contains no delimiter character, unless
the -s option is specified
-n (ignored)
--complement complement the set of selected bytes, characters
or fields
-s, --only-delimited do not print lines not containing delimiters
--output-delimiter=STRING use STRING as the output delimiter
the default is to use the input delimiter
-z, --zero-terminated line delimiter is NUL, not newline
--help display this help and exit
--version output version information and exit
Use one, and only one of -b, -c or -f. Each LIST is made up of one
range, or many ranges separated by commas. Selected input is written
in the same order that it is read, and is written exactly once.
Each range is one of:
N N'th byte, character or field, counted from 1
N- from N'th byte, character or field, to end of line
N-M from N'th to M'th (included) byte, character or field
-M from first to M'th (included) byte, character or field
GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
Full documentation <https://www.gnu.org/software/coreutils/cut>
or available locally via: info '(coreutils) cut invocation'
date
Print or set the system date and time.
user $date --helpUsage: date [OPTION]... [+FORMAT]
or: date [-u|--utc|--universal] [MMDDhhmm[[CC]YY][.ss]]
Display the current time in the given FORMAT, or set the system date.
Mandatory arguments to long options are mandatory for short options too.
-d, --date=STRING display time described by STRING, not 'now'
--debug annotate the parsed date,
and warn about questionable usage to stderr
-f, --file=DATEFILE like --date; once for each line of DATEFILE
-I[FMT], --iso-8601[=FMT] output date/time in ISO 8601 format.
FMT='date' for date only (the default),
'hours', 'minutes', 'seconds', or 'ns'
for date and time to the indicated precision.
Example: 2006-08-14T02:34:56-06:00
-R, --rfc-email output date and time in RFC 5322 format.
Example: Mon, 14 Aug 2006 02:34:56 -0600
--rfc-3339=FMT output date/time in RFC 3339 format.
FMT='date', 'seconds', or 'ns'
for date and time to the indicated precision.
Example: 2006-08-14 02:34:56-06:00
-r, --reference=FILE display the last modification time of FILE
-s, --set=STRING set time described by STRING
-u, --utc, --universal print or set Coordinated Universal Time (UTC)
--help display this help and exit
--version output version information and exit
FORMAT controls the output. Interpreted sequences are:
%% a literal %
%a locale's abbreviated weekday name (e.g., Sun)
%A locale's full weekday name (e.g., Sunday)
%b locale's abbreviated month name (e.g., Jan)
%B locale's full month name (e.g., January)
%c locale's date and time (e.g., Thu Mar 3 23:05:25 2005)
%C century; like %Y, except omit last two digits (e.g., 20)
%d day of month (e.g., 01)
%D date; same as %m/%d/%y
%e day of month, space padded; same as %_d
%F full date; like %+4Y-%m-%d
%g last two digits of year of ISO week number (see %G)
%G year of ISO week number (see %V); normally useful only with %V
%h same as %b
%H hour (00..23)
%I hour (01..12)
%j day of year (001..366)
%k hour, space padded ( 0..23); same as %_H
%l hour, space padded ( 1..12); same as %_I
%m month (01..12)
%M minute (00..59)
%n a newline
%N nanoseconds (000000000..999999999)
%p locale's equivalent of either AM or PM; blank if not known
%P like %p, but lower case
%q quarter of year (1..4)
%r locale's 12-hour clock time (e.g., 11:11:04 PM)
%R 24-hour hour and minute; same as %H:%M
%s seconds since 1970-01-01 00:00:00 UTC
%S second (00..60)
%t a tab
%T time; same as %H:%M:%S
%u day of week (1..7); 1 is Monday
%U week number of year, with Sunday as first day of week (00..53)
%V ISO week number, with Monday as first day of week (01..53)
%w day of week (0..6); 0 is Sunday
%W week number of year, with Monday as first day of week (00..53)
%x locale's date representation (e.g., 12/31/99)
%X locale's time representation (e.g., 23:13:48)
%y last two digits of year (00..99)
%Y year
%z +hhmm numeric time zone (e.g., -0400)
%:z +hh:mm numeric time zone (e.g., -04:00)
%::z +hh:mm:ss numeric time zone (e.g., -04:00:00)
%:::z numeric time zone with : to necessary precision (e.g., -04, +05:30)
%Z alphabetic time zone abbreviation (e.g., EDT)
By default, date pads numeric fields with zeroes.
The following optional flags may follow '%':
- (hyphen) do not pad the field
_ (underscore) pad with spaces
0 (zero) pad with zeros
+ pad with zeros, and put '+' before future years with >4 digits
^ use upper case if possible
# use opposite case if possible
After any flags comes an optional field width, as a decimal number;
then an optional modifier, which is either
E to use the locale's alternate representations if available, or
O to use the locale's alternate numeric symbols if available.
Examples:
Convert seconds since the epoch (1970-01-01 UTC) to a date
$ date --date='@2147483647'
Show the time on the west coast of the US (use tzselect(1) to find TZ)
$ TZ='America/Los_Angeles' date
Show the local time for 9AM next Friday on the west coast of the US
$ date --date='TZ="America/Los_Angeles" 09:00 next Fri'
GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
Full documentation <https://www.gnu.org/software/coreutils/date>
or available locally via: info '(coreutils) date invocation'
dd
Convert and copy a file. See the dd article.
user $dd --helpUsage: dd [OPERAND]...
or: dd OPTION
Copy a file, converting and formatting according to the operands.
bs=BYTES read and write up to BYTES bytes at a time (default: 512);
overrides ibs and obs
cbs=BYTES convert BYTES bytes at a time
conv=CONVS convert the file as per the comma separated symbol list
count=N copy only N input blocks
ibs=BYTES read up to BYTES bytes at a time (default: 512)
if=FILE read from FILE instead of stdin
iflag=FLAGS read as per the comma separated symbol list
obs=BYTES write BYTES bytes at a time (default: 512)
of=FILE write to FILE instead of stdout
oflag=FLAGS write as per the comma separated symbol list
seek=N skip N obs-sized blocks at start of output
skip=N skip N ibs-sized blocks at start of input
status=LEVEL The LEVEL of information to print to stderr;
'none' suppresses everything but error messages,
'noxfer' suppresses the final transfer statistics,
'progress' shows periodic transfer statistics
N and BYTES may be followed by the following multiplicative suffixes:
c=1, w=2, b=512, kB=1000, K=1024, MB=1000*1000, M=1024*1024, xM=M,
GB=1000*1000*1000, G=1024*1024*1024, and so on for T, P, E, Z, Y.
Binary prefixes can be used, too: KiB=K, MiB=M, and so on.
Each CONV symbol may be:
ascii from EBCDIC to ASCII
ebcdic from ASCII to EBCDIC
ibm from ASCII to alternate EBCDIC
block pad newline-terminated records with spaces to cbs-size
unblock replace trailing spaces in cbs-size records with newline
lcase change upper case to lower case
ucase change lower case to upper case
sparse try to seek rather than write all-NUL output blocks
swab swap every pair of input bytes
sync pad every input block with NULs to ibs-size; when used
with block or unblock, pad with spaces rather than NULs
excl fail if the output file already exists
nocreat do not create the output file
notrunc do not truncate the output file
noerror continue after read errors
fdatasync physically write output file data before finishing
fsync likewise, but also write metadata
Each FLAG symbol may be:
append append mode (makes sense only for output; conv=notrunc suggested)
direct use direct I/O for data
directory fail unless a directory
dsync use synchronized I/O for data
sync likewise, but also for metadata
fullblock accumulate full blocks of input (iflag only)
nonblock use non-blocking I/O
noatime do not update access time
nocache Request to drop cache. See also oflag=sync
noctty do not assign controlling terminal from file
nofollow do not follow symlinks
count_bytes treat 'count=N' as a byte count (iflag only)
skip_bytes treat 'skip=N' as a byte count (iflag only)
seek_bytes treat 'seek=N' as a byte count (oflag only)
Sending a USR1 signal to a running 'dd' process makes it
print I/O statistics to standard error and then resume copying.
Options are:
--help display this help and exit
--version output version information and exit
GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
Full documentation <https://www.gnu.org/software/coreutils/dd>
or available locally via: info '(coreutils) dd invocation'
Warning
Misuse of the dd command can easily result in severe data loss.
Misuse of the dd command can easily result in severe data loss.
df
Report file system disk space usage.
user $df --helpUsage: /bin/df [OPTION]... [FILE]...
Show information about the file system on which each FILE resides,
or all file systems by default.
Mandatory arguments to long options are mandatory for short options too.
-a, --all include pseudo, duplicate, inaccessible file systems
-B, --block-size=SIZE scale sizes by SIZE before printing them; e.g.,
'-BM' prints sizes in units of 1,048,576 bytes;
see SIZE format below
-h, --human-readable print sizes in powers of 1024 (e.g., 1023M)
-H, --si print sizes in powers of 1000 (e.g., 1.1G)
-i, --inodes list inode information instead of block usage
-k like --block-size=1K
-l, --local limit listing to local file systems
--no-sync do not invoke sync before getting usage info (default)
--output[=FIELD_LIST] use the output format defined by FIELD_LIST,
or print all fields if FIELD_LIST is omitted.
-P, --portability use the POSIX output format
--sync invoke sync before getting usage info
--total elide all entries insignificant to available space,
and produce a grand total
-t, --type=TYPE limit listing to file systems of type TYPE
-T, --print-type print file system type
-x, --exclude-type=TYPE limit listing to file systems not of type TYPE
-v (ignored)
--help display this help and exit
--version output version information and exitdir
List directory contents.
user $dir --helpUsage: dir [OPTION]... [FILE]...
List information about the FILEs (the current directory by default).
Sort entries alphabetically if none of -cftuvSUX nor --sort is specified.
Mandatory arguments to long options are mandatory for short options too.
-a, --all do not ignore entries starting with .
-A, --almost-all do not list implied . and ..
--author with -l, print the author of each file
-b, --escape print C-style escapes for nongraphic characters
--block-size=SIZE with -l, scale sizes by SIZE when printing them;
e.g., '--block-size=M'; see SIZE format below
-B, --ignore-backups do not list implied entries ending with ~
-c with -lt: sort by, and show, ctime (time of last
modification of file status information);
with -l: show ctime and sort by name;
otherwise: sort by ctime, newest first
-C list entries by columns
--color[=WHEN] colorize the output; WHEN can be 'always' (default
if omitted), 'auto', or 'never'; more info below
-d, --directory list directories themselves, not their contents
-D, --dired generate output designed for Emacs' dired mode
-f do not sort, enable -aU, disable -ls --color
-F, --classify append indicator (one of */=>@|) to entries
--file-type likewise, except do not append '*'
--format=WORD across -x, commas -m, horizontal -x, long -l,
single-column -1, verbose -l, vertical -C
--full-time like -l --time-style=full-iso
-g like -l, but do not list owner
--group-directories-first
group directories before files;
can be augmented with a --sort option, but any
use of --sort=none (-U) disables grouping
-G, --no-group in a long listing, don't print group names
-h, --human-readable with -l and -s, print sizes like 1K 234M 2G etc.
--si likewise, but use powers of 1000 not 1024
-H, --dereference-command-line
follow symbolic links listed on the command line
--dereference-command-line-symlink-to-dir
follow each command line symbolic link
that points to a directory
--hide=PATTERN do not list implied entries matching shell PATTERN
(overridden by -a or -A)
--hyperlink[=WHEN] hyperlink file names; WHEN can be 'always'
(default if omitted), 'auto', or 'never'
--indicator-style=WORD append indicator with style WORD to entry names:
none (default), slash (-p),
file-type (--file-type), classify (-F)
-i, --inode print the index number of each file
-I, --ignore=PATTERN do not list implied entries matching shell PATTERN
-k, --kibibytes default to 1024-byte blocks for disk usage;
used only with -s and per directory totals
-l use a long listing format
-L, --dereference when showing file information for a symbolic
link, show information for the file the link
references rather than for the link itself
-m fill width with a comma separated list of entries
-n, --numeric-uid-gid like -l, but list numeric user and group IDs
-N, --literal print entry names without quoting
-o like -l, but do not list group information
-p, --indicator-style=slash
append / indicator to directories
-q, --hide-control-chars print ? instead of nongraphic characters
--show-control-chars show nongraphic characters as-is (the default,
unless program is 'ls' and output is a terminal)
-Q, --quote-name enclose entry names in double quotes
--quoting-style=WORD use quoting style WORD for entry names:
literal, locale, shell, shell-always,
shell-escape, shell-escape-always, c, escape
(overrides QUOTING_STYLE environment variable)
-r, --reverse reverse order while sorting
-R, --recursive list subdirectories recursively
-s, --size print the allocated size of each file, in blocks
-S sort by file size, largest first
--sort=WORD sort by WORD instead of name: none (-U), size (-S),
time (-t), version (-v), extension (-X)
--time=WORD change the default of using modification times;
access time (-u): atime, access, use;
change time (-c): ctime, status;
birth time: birth, creation;
with -l, WORD determines which time to show;
with --sort=time, sort by WORD (newest first)
--time-style=TIME_STYLE time/date format with -l; see TIME_STYLE below
-t sort by time, newest first; see --time
-T, --tabsize=COLS assume tab stops at each COLS instead of 8
-u with -lt: sort by, and show, access time;
with -l: show access time and sort by name;
otherwise: sort by access time, newest first
-U do not sort; list entries in directory order
-v natural sort of (version) numbers within text
-w, --width=COLS set output width to COLS. 0 means no limit
-x list entries by lines instead of by columns
-X sort alphabetically by entry extension
-Z, --context print any security context of each file
-1 list one file per line. Avoid '\n' with -q or -b
--help display this help and exit
--version output version information and exit
The SIZE argument is an integer and optional unit (example: 10K is 10*1024).
Units are K,M,G,T,P,E,Z,Y (powers of 1024) or KB,MB,... (powers of 1000).
Binary prefixes can be used, too: KiB=K, MiB=M, and so on.
The TIME_STYLE argument can be full-iso, long-iso, iso, locale, or +FORMAT.
FORMAT is interpreted like in date(1). If FORMAT is FORMAT1<newline>FORMAT2,
then FORMAT1 applies to non-recent files and FORMAT2 to recent files.
TIME_STYLE prefixed with 'posix-' takes effect only outside the POSIX locale.
Also the TIME_STYLE environment variable sets the default style to use.
Using color to distinguish file types is disabled both by default and
with --color=never. With --color=auto, ls emits color codes only when
standard output is connected to a terminal. The LS_COLORS environment
variable can change the settings. Use the dircolors command to set it.
Exit status:
0 if OK,
1 if minor problems (e.g., cannot access subdirectory),
2 if serious trouble (e.g., cannot access command-line argument).
GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
Full documentation <https://www.gnu.org/software/coreutils/dir>
or available locally via: info '(coreutils) dir invocation'
dircolors
Color setup for ls.
user $dircolors --helpUsage: dircolors [OPTION]... [FILE]
Output commands to set the LS_COLORS environment variable.
Determine format of output:
-b, --sh, --bourne-shell output Bourne shell code to set LS_COLORS
-c, --csh, --c-shell output C shell code to set LS_COLORS
-p, --print-database output defaults
--help display this help and exit
--version output version information and exit
If FILE is specified, read it to determine which colors to use for which
file types and extensions. Otherwise, a precompiled database is used.
For details on the format of these files, run 'dircolors --print-database'.
GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
Full documentation <https://www.gnu.org/software/coreutils/dircolors>
or available locally via: info '(coreutils) dircolors invocation'
dirname
Strip last component from file name.
user $dirname --helpUsage: dirname [OPTION] NAME...
Output each NAME with its last non-slash component and trailing slashes
removed; if NAME contains no /'s, output '.' (meaning the current directory).
-z, --zero end each output line with NUL, not newline
--help display this help and exit
--version output version information and exit
Examples:
dirname /usr/bin/ -> "/usr"
dirname dir1/str dir2/str -> "dir1" followed by "dir2"
dirname stdio.h -> "."
GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
Full documentation <https://www.gnu.org/software/coreutils/dirname>
or available locally via: info '(coreutils) dirname invocation'
du
Estimate file space usage.
user $du --helpUsage: du [OPTION]... [FILE]...
or: du [OPTION]... --files0-from=F
Summarize disk usage of the set of FILEs, recursively for directories.
Mandatory arguments to long options are mandatory for short options too.
-0, --null end each output line with NUL, not newline
-a, --all write counts for all files, not just directories
--apparent-size print apparent sizes, rather than disk usage; although
the apparent size is usually smaller, it may be
larger due to holes in ('sparse') files, internal
fragmentation, indirect blocks, and the like
-B, --block-size=SIZE scale sizes by SIZE before printing them; e.g.,
'-BM' prints sizes in units of 1,048,576 bytes;
see SIZE format below
-b, --bytes equivalent to '--apparent-size --block-size=1'
-c, --total produce a grand total
-D, --dereference-args dereference only symlinks that are listed on the
command line
-d, --max-depth=N print the total for a directory (or file, with --all)
only if it is N or fewer levels below the command
line argument; --max-depth=0 is the same as
--summarize
--files0-from=F summarize disk usage of the
NUL-terminated file names specified in file F;
if F is -, then read names from standard input
-H equivalent to --dereference-args (-D)
-h, --human-readable print sizes in human readable format (e.g., 1K 234M 2G)
--inodes list inode usage information instead of block usage
-k like --block-size=1K
-L, --dereference dereference all symbolic links
-l, --count-links count sizes many times if hard linked
-m like --block-size=1M
-P, --no-dereference don't follow any symbolic links (this is the default)
-S, --separate-dirs for directories do not include size of subdirectories
--si like -h, but use powers of 1000 not 1024
-s, --summarize display only a total for each argument
-t, --threshold=SIZE exclude entries smaller than SIZE if positive,
or entries greater than SIZE if negative
--time show time of the last modification of any file in the
directory, or any of its subdirectories
--time=WORD show time as WORD instead of modification time:
atime, access, use, ctime or status
--time-style=STYLE show times using STYLE, which can be:
full-iso, long-iso, iso, or +FORMAT;
FORMAT is interpreted like in 'date'
-X, --exclude-from=FILE exclude files that match any pattern in FILE
--exclude=PATTERN exclude files that match PATTERN
-x, --one-file-system skip directories on different file systems
--help display this help and exit
--version output version information and exit
Display values are in units of the first available SIZE from --block-size,
and the DU_BLOCK_SIZE, BLOCK_SIZE and BLOCKSIZE environment variables.
Otherwise, units default to 1024 bytes (or 512 if POSIXLY_CORRECT is set).
The SIZE argument is an integer and optional unit (example: 10K is 10*1024).
Units are K,M,G,T,P,E,Z,Y (powers of 1024) or KB,MB,... (powers of 1000).
Binary prefixes can be used, too: KiB=K, MiB=M, and so on.
GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
Full documentation <https://www.gnu.org/software/coreutils/du>
or available locally via: info '(coreutils) du invocation'
echo
Display a line of text.
user $/bin/echo --helpUsage: /bin/echo [SHORT-OPTION]... [STRING]...
or: /bin/echo LONG-OPTION
Echo the STRING(s) to standard output.
-n do not output the trailing newline
-e enable interpretation of backslash escapes
-E disable interpretation of backslash escapes (default)
--help display this help and exit
--version output version information and exit
If -e is in effect, the following sequences are recognized:
\\ backslash
\a alert (BEL)
\b backspace
\c produce no further output
\e escape
\f form feed
\n new line
\r carriage return
\t horizontal tab
\v vertical tab
\0NNN byte with octal value NNN (1 to 3 digits)
\xHH byte with hexadecimal value HH (1 to 2 digits)
NOTE: your shell may have its own version of echo, which usually supersedes
the version described here. Please refer to your shell's documentation
for details about the options it supports.
GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
Full documentation <https://www.gnu.org/software/coreutils/echo>
or available locally via: info '(coreutils) echo invocation'
n.b. Some shells have an echo command built in, which is why this needs the /bin prefix to return the help text.
env
Run a program in a modified environment.
user $env --helpUsage: env [OPTION]... [-] [NAME=VALUE]... [COMMAND [ARG]...]
Set each NAME to VALUE in the environment and run COMMAND.
Mandatory arguments to long options are mandatory for short options too.
-i, --ignore-environment start with an empty environment
-0, --null end each output line with NUL, not newline
-u, --unset=NAME remove variable from the environment
-C, --chdir=DIR change working directory to DIR
-S, --split-string=S process and split S into separate arguments;
used to pass multiple arguments on shebang lines
--block-signal[=SIG] block delivery of SIG signal(s) to COMMAND
--default-signal[=SIG] reset handling of SIG signal(s) to the default
--ignore-signal[=SIG] set handling of SIG signals(s) to do nothing
--list-signal-handling list non default signal handling to stderr
-v, --debug print verbose information for each processing step
--help display this help and exit
--version output version information and exit
A mere - implies -i. If no COMMAND, print the resulting environment.
SIG may be a signal name like 'PIPE', or a signal number like '13'.
Without SIG, all known signals are included. Multiple signals can be
comma-separated.
GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
Full documentation <https://www.gnu.org/software/coreutils/env>
or available locally via: info '(coreutils) env invocation'
expand
Convert tabs to spaces.
user $expand --helpUsage: expand [OPTION]... [FILE]...
Convert tabs in each FILE to spaces, writing to standard output.
With no FILE, or when FILE is -, read standard input.
Mandatory arguments to long options are mandatory for short options too.
-i, --initial do not convert tabs after non blanks
-t, --tabs=N have tabs N characters apart, not 8
-t, --tabs=LIST use comma separated list of tab positions
The last specified position can be prefixed with '/'
to specify a tab size to use after the last
explicitly specified tab stop. Also a prefix of '+'
can be used to align remaining tab stops relative to
the last specified tab stop instead of the first column
--help display this help and exit
--version output version information and exit
GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
Full documentation <https://www.gnu.org/software/coreutils/expand>
or available locally via: info '(coreutils) expand invocation'
expr
Evaluate expressions.
user $expr --helpUsage: expr EXPRESSION
or: expr OPTION
--help display this help and exit
--version output version information and exit
Print the value of EXPRESSION to standard output. A blank line below
separates increasing precedence groups. EXPRESSION may be:
ARG1 | ARG2 ARG1 if it is neither null nor 0, otherwise ARG2
ARG1 & ARG2 ARG1 if neither argument is null or 0, otherwise 0
ARG1 < ARG2 ARG1 is less than ARG2
ARG1 <= ARG2 ARG1 is less than or equal to ARG2
ARG1 = ARG2 ARG1 is equal to ARG2
ARG1 != ARG2 ARG1 is unequal to ARG2
ARG1 >= ARG2 ARG1 is greater than or equal to ARG2
ARG1 > ARG2 ARG1 is greater than ARG2
ARG1 + ARG2 arithmetic sum of ARG1 and ARG2
ARG1 - ARG2 arithmetic difference of ARG1 and ARG2
ARG1 * ARG2 arithmetic product of ARG1 and ARG2
ARG1 / ARG2 arithmetic quotient of ARG1 divided by ARG2
ARG1 % ARG2 arithmetic remainder of ARG1 divided by ARG2
STRING : REGEXP anchored pattern match of REGEXP in STRING
match STRING REGEXP same as STRING : REGEXP
substr STRING POS LENGTH substring of STRING, POS counted from 1
index STRING CHARS index in STRING where any CHARS is found, or 0
length STRING length of STRING
+ TOKEN interpret TOKEN as a string, even if it is a
keyword like 'match' or an operator like '/'
( EXPRESSION ) value of EXPRESSION
Beware that many operators need to be escaped or quoted for shells.
Comparisons are arithmetic if both ARGs are numbers, else lexicographical.
Pattern matches return the string matched between \( and \) or null; if
\( and \) are not used, they return the number of characters matched or 0.
Exit status is 0 if EXPRESSION is neither null nor 0, 1 if EXPRESSION is null
or 0, 2 if EXPRESSION is syntactically invalid, and 3 if an error occurred.
GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
Full documentation <https://www.gnu.org/software/coreutils/expr>
or available locally via: info '(coreutils) expr invocation'
factor
Factor numbers.
user $factor --helpUsage: factor [NUMBER]...
or: factor OPTION
Print the prime factors of each specified integer NUMBER. If none
are specified on the command line, read them from standard input.
--help display this help and exit
--version output version information and exit
GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
Full documentation <https://www.gnu.org/software/coreutils/factor>
or available locally via: info '(coreutils) factor invocation'
false
Do nothing, unsuccessfully.
user $/bin/false --helpUsage: /bin/false [ignored command line arguments]
or: /bin/false OPTION
Exit with a status code indicating failure.
--help display this help and exit
--version output version information and exit
NOTE: your shell may have its own version of false, which usually supersedes
the version described here. Please refer to your shell's documentation
for details about the options it supports.
GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
Full documentation <https://www.gnu.org/software/coreutils/false>
or available locally via: info '(coreutils) false invocation'
n.b. Some shells have a false command built in, which is why this needs the /bin prefix to return the help text.
fmt
Simple optimal text formatter.
user $fmt --helpUsage: fmt [-WIDTH] [OPTION]... [FILE]...
Reformat each paragraph in the FILE(s), writing to standard output.
The option -WIDTH is an abbreviated form of --width=DIGITS.
With no FILE, or when FILE is -, read standard input.
Mandatory arguments to long options are mandatory for short options too.
-c, --crown-margin preserve indentation of first two lines
-p, --prefix=STRING reformat only lines beginning with STRING,
reattaching the prefix to reformatted lines
-s, --split-only split long lines, but do not refill
-t, --tagged-paragraph indentation of first line different from second
-u, --uniform-spacing one space between words, two after sentences
-w, --width=WIDTH maximum line width (default of 75 columns)
-g, --goal=WIDTH goal width (default of 93% of width)
--help display this help and exit
--version output version information and exit
GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
Full documentation <https://www.gnu.org/software/coreutils/fmt>
or available locally via: info '(coreutils) fmt invocation'
fold
Wrap each input line to fit in specified width.
user $fold --helpUsage: fold [OPTION]... [FILE]...
Wrap input lines in each FILE, writing to standard output.
With no FILE, or when FILE is -, read standard input.
Mandatory arguments to long options are mandatory for short options too.
-b, --bytes count bytes rather than columns
-s, --spaces break at spaces
-w, --width=WIDTH use WIDTH columns instead of 80
--help display this help and exit
--version output version information and exit
GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
Full documentation <https://www.gnu.org/software/coreutils/fold>
or available locally via: info '(coreutils) fold invocation'
head
Output the first part of files.
user $head --helpUsage: head [OPTION]... [FILE]...
Print the first 10 lines of each FILE to standard output.
With more than one FILE, precede each with a header giving the file name.
With no FILE, or when FILE is -, read standard input.
Mandatory arguments to long options are mandatory for short options too.
-c, --bytes=[-]NUM print the first NUM bytes of each file;
with the leading '-', print all but the last
NUM bytes of each file
-n, --lines=[-]NUM print the first NUM lines instead of the first 10;
with the leading '-', print all but the last
NUM lines of each file
-q, --quiet, --silent never print headers giving file names
-v, --verbose always print headers giving file names
-z, --zero-terminated line delimiter is NUL, not newline
--help display this help and exit
--version output version information and exit
NUM may have a multiplier suffix:
b 512, kB 1000, K 1024, MB 1000*1000, M 1024*1024,
GB 1000*1000*1000, G 1024*1024*1024, and so on for T, P, E, Z, Y.
Binary prefixes can be used, too: KiB=K, MiB=M, and so on.
GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
Full documentation <https://www.gnu.org/software/coreutils/head>
or available locally via: info '(coreutils) head invocation'
hostid
Print the numeric identifier for the current host.
user $hostid --helpUsage: hostid [OPTION]
Print the numeric identifier (in hexadecimal) for the current host.
--help display this help and exit
--version output version information and exit
GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
Full documentation <https://www.gnu.org/software/coreutils/hostid>
or available locally via: info '(coreutils) hostid invocation'
id
Print real and effective user and group IDs.
user $id --helpUsage: id [OPTION]... [USER]...
Print user and group information for each specified USER,
or (when USER omitted) for the current user.
-a ignore, for compatibility with other versions
-Z, --context print only the security context of the process
-g, --group print only the effective group ID
-G, --groups print all group IDs
-n, --name print a name instead of a number, for -ugG
-r, --real print the real ID instead of the effective ID, with -ugG
-u, --user print only the effective user ID
-z, --zero delimit entries with NUL characters, not whitespace;
not permitted in default format
--help display this help and exit
--version output version information and exit
Without any OPTION, print some useful set of identified information.
GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
Full documentation <https://www.gnu.org/software/coreutils/id>
or available locally via: info '(coreutils) id invocation'
install
Copy files and set attributes.
user $install --helpUsage: install [OPTION]... [-T] SOURCE DEST
or: install [OPTION]... SOURCE... DIRECTORY
or: install [OPTION]... -t DIRECTORY SOURCE...
or: install [OPTION]... -d DIRECTORY...
This install program copies files (often just compiled) into destination
locations you choose. If you want to download and install a ready-to-use
package on a GNU/Linux system, you should instead be using a package manager
like yum(1) or apt-get(1).
In the first three forms, copy SOURCE to DEST or multiple SOURCE(s) to
the existing DIRECTORY, while setting permission modes and owner/group.
In the 4th form, create all components of the given DIRECTORY(ies).
Mandatory arguments to long options are mandatory for short options too.
--backup[=CONTROL] make a backup of each existing destination file
-b like --backup but does not accept an argument
-c (ignored)
-C, --compare compare each pair of source and destination files, and
in some cases, do not modify the destination at all
-d, --directory treat all arguments as directory names; create all
components of the specified directories
-D create all leading components of DEST except the last,
or all components of --target-directory,
then copy SOURCE to DEST
-g, --group=GROUP set group ownership, instead of process' current group
-m, --mode=MODE set permission mode (as in chmod), instead of rwxr-xr-x
-o, --owner=OWNER set ownership (super-user only)
-p, --preserve-timestamps apply access/modification times of SOURCE files
to corresponding destination files
-s, --strip strip symbol tables
--strip-program=PROGRAM program used to strip binaries
-S, --suffix=SUFFIX override the usual backup suffix
-t, --target-directory=DIRECTORY copy all SOURCE arguments into DIRECTORY
-T, --no-target-directory treat DEST as a normal file
-v, --verbose print the name of each directory as it is created
--preserve-context preserve SELinux security context
-Z set SELinux security context of destination
file and each created directory to default type
--context[=CTX] like -Z, or if CTX is specified then set the
SELinux or SMACK security context to CTX
--help display this help and exit
--version output version information and exit
The backup suffix is '~', unless set with --suffix or SIMPLE_BACKUP_SUFFIX.
The version control method may be selected via the --backup option or through
the VERSION_CONTROL environment variable. Here are the values:
none, off never make backups (even if --backup is given)
numbered, t make numbered backups
existing, nil numbered if numbered backups exist, simple otherwise
simple, never always make simple backups
GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
Full documentation <https://www.gnu.org/software/coreutils/install>
or available locally via: info '(coreutils) install invocation'
join
Join lines of two files on a common field.
user $join --helpUsage: join [OPTION]... FILE1 FILE2
For each pair of input lines with identical join fields, write a line to
standard output. The default join field is the first, delimited by blanks.
When FILE1 or FILE2 (not both) is -, read standard input.
-a FILENUM also print unpairable lines from file FILENUM, where
FILENUM is 1 or 2, corresponding to FILE1 or FILE2
-e EMPTY replace missing input fields with EMPTY
-i, --ignore-case ignore differences in case when comparing fields
-j FIELD equivalent to '-1 FIELD -2 FIELD'
-o FORMAT obey FORMAT while constructing output line
-t CHAR use CHAR as input and output field separator
-v FILENUM like -a FILENUM, but suppress joined output lines
-1 FIELD join on this FIELD of file 1
-2 FIELD join on this FIELD of file 2
--check-order check that the input is correctly sorted, even
if all input lines are pairable
--nocheck-order do not check that the input is correctly sorted
--header treat the first line in each file as field headers,
print them without trying to pair them
-z, --zero-terminated line delimiter is NUL, not newline
--help display this help and exit
--version output version information and exit
Unless -t CHAR is given, leading blanks separate fields and are ignored,
else fields are separated by CHAR. Any FIELD is a field number counted
from 1. FORMAT is one or more comma or blank separated specifications,
each being 'FILENUM.FIELD' or '0'. Default FORMAT outputs the join field,
the remaining fields from FILE1, the remaining fields from FILE2, all
separated by CHAR. If FORMAT is the keyword 'auto', then the first
line of each file determines the number of fields output for each line.
Important: FILE1 and FILE2 must be sorted on the join fields.
E.g., use "sort -k 1b,1" if 'join' has no options,
or use "join -t ''" if 'sort' has no options.
Note, comparisons honor the rules specified by 'LC_COLLATE'.
If the input is not sorted and some lines cannot be joined, a
warning message will be given.
GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
Full documentation <https://www.gnu.org/software/coreutils/join>
or available locally via: info '(coreutils) join invocation'
link
Call the link function to create a link to a file.
user $link --helpUsage: link FILE1 FILE2
or: link OPTION
Call the link function to create a link named FILE2 to an existing FILE1.
--help display this help and exit
--version output version information and exit
GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
Full documentation <https://www.gnu.org/software/coreutils/link>
or available locally via: info '(coreutils) link invocation'
ln
Make links between files.
user $ln --helpUsage: ln [OPTION]... [-T] TARGET LINK_NAME
or: ln [OPTION]... TARGET
or: ln [OPTION]... TARGET... DIRECTORY
or: ln [OPTION]... -t DIRECTORY TARGET...
In the 1st form, create a link to TARGET with the name LINK_NAME.
In the 2nd form, create a link to TARGET in the current directory.
In the 3rd and 4th forms, create links to each TARGET in DIRECTORY.
Create hard links by default, symbolic links with --symbolic.
By default, each destination (name of new link) should not already exist.
When creating hard links, each TARGET must exist. Symbolic links
can hold arbitrary text; if later resolved, a relative link is
interpreted in relation to its parent directory.
Mandatory arguments to long options are mandatory for short options too.
--backup[=CONTROL] make a backup of each existing destination file
-b like --backup but does not accept an argument
-d, -F, --directory allow the superuser to attempt to hard link
directories (note: will probably fail due to
system restrictions, even for the superuser)
-f, --force remove existing destination files
-i, --interactive prompt whether to remove destinations
-L, --logical dereference TARGETs that are symbolic links
-n, --no-dereference treat LINK_NAME as a normal file if
it is a symbolic link to a directory
-P, --physical make hard links directly to symbolic links
-r, --relative create symbolic links relative to link location
-s, --symbolic make symbolic links instead of hard links
-S, --suffix=SUFFIX override the usual backup suffix
-t, --target-directory=DIRECTORY specify the DIRECTORY in which to create
the links
-T, --no-target-directory treat LINK_NAME as a normal file always
-v, --verbose print name of each linked file
--help display this help and exit
--version output version information and exit
The backup suffix is '~', unless set with --suffix or SIMPLE_BACKUP_SUFFIX.
The version control method may be selected via the --backup option or through
the VERSION_CONTROL environment variable. Here are the values:
none, off never make backups (even if --backup is given)
numbered, t make numbered backups
existing, nil numbered if numbered backups exist, simple otherwise
simple, never always make simple backups
Using -s ignores -L and -P. Otherwise, the last option specified controls
behavior when a TARGET is a symbolic link, defaulting to -P.
GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
Full documentation <https://www.gnu.org/software/coreutils/ln>
or available locally via: info '(coreutils) ln invocation'
logname
Print user's login name.
user $logname --helpUsage: logname [OPTION]
Print the name of the current user.
--help display this help and exit
--version output version information and exit
GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
Full documentation <https://www.gnu.org/software/coreutils/logname>
or available locally via: info '(coreutils) logname invocation'
ls
List directory contents.
user $ls --helpUsage: ls [OPTION]... [FILE]...
List information about the FILEs (the current directory by default).
Sort entries alphabetically if none of -cftuvSUX nor --sort is specified.
Mandatory arguments to long options are mandatory for short options too.
-a, --all do not ignore entries starting with .
-A, --almost-all do not list implied . and ..
--author with -l, print the author of each file
-b, --escape print C-style escapes for nongraphic characters
--block-size=SIZE with -l, scale sizes by SIZE when printing them;
e.g., '--block-size=M'; see SIZE format below
-B, --ignore-backups do not list implied entries ending with ~
-c with -lt: sort by, and show, ctime (time of last
modification of file status information);
with -l: show ctime and sort by name;
otherwise: sort by ctime, newest first
-C list entries by columns
--color[=WHEN] colorize the output; WHEN can be 'always' (default
if omitted), 'auto', or 'never'; more info below
-d, --directory list directories themselves, not their contents
-D, --dired generate output designed for Emacs' dired mode
-f do not sort, enable -aU, disable -ls --color
-F, --classify append indicator (one of */=>@|) to entries
--file-type likewise, except do not append '*'
--format=WORD across -x, commas -m, horizontal -x, long -l,
single-column -1, verbose -l, vertical -C
--full-time like -l --time-style=full-iso
-g like -l, but do not list owner
--group-directories-first
group directories before files;
can be augmented with a --sort option, but any
use of --sort=none (-U) disables grouping
-G, --no-group in a long listing, don't print group names
-h, --human-readable with -l and -s, print sizes like 1K 234M 2G etc.
--si likewise, but use powers of 1000 not 1024
-H, --dereference-command-line
follow symbolic links listed on the command line
--dereference-command-line-symlink-to-dir
follow each command line symbolic link
that points to a directory
--hide=PATTERN do not list implied entries matching shell PATTERN
(overridden by -a or -A)
--hyperlink[=WHEN] hyperlink file names; WHEN can be 'always'
(default if omitted), 'auto', or 'never'
--indicator-style=WORD append indicator with style WORD to entry names:
none (default), slash (-p),
file-type (--file-type), classify (-F)
-i, --inode print the index number of each file
-I, --ignore=PATTERN do not list implied entries matching shell PATTERN
-k, --kibibytes default to 1024-byte blocks for disk usage;
used only with -s and per directory totals
-l use a long listing format
-L, --dereference when showing file information for a symbolic
link, show information for the file the link
references rather than for the link itself
-m fill width with a comma separated list of entries
-n, --numeric-uid-gid like -l, but list numeric user and group IDs
-N, --literal print entry names without quoting
-o like -l, but do not list group information
-p, --indicator-style=slash
append / indicator to directories
-q, --hide-control-chars print ? instead of nongraphic characters
--show-control-chars show nongraphic characters as-is (the default,
unless program is 'ls' and output is a terminal)
-Q, --quote-name enclose entry names in double quotes
--quoting-style=WORD use quoting style WORD for entry names:
literal, locale, shell, shell-always,
shell-escape, shell-escape-always, c, escape
(overrides QUOTING_STYLE environment variable)
-r, --reverse reverse order while sorting
-R, --recursive list subdirectories recursively
-s, --size print the allocated size of each file, in blocks
-S sort by file size, largest first
--sort=WORD sort by WORD instead of name: none (-U), size (-S),
time (-t), version (-v), extension (-X)
--time=WORD change the default of using modification times;
access time (-u): atime, access, use;
change time (-c): ctime, status;
birth time: birth, creation;
with -l, WORD determines which time to show;
with --sort=time, sort by WORD (newest first)
--time-style=TIME_STYLE time/date format with -l; see TIME_STYLE below
-t sort by time, newest first; see --time
-T, --tabsize=COLS assume tab stops at each COLS instead of 8
-u with -lt: sort by, and show, access time;
with -l: show access time and sort by name;
otherwise: sort by access time, newest first
-U do not sort; list entries in directory order
-v natural sort of (version) numbers within text
-w, --width=COLS set output width to COLS. 0 means no limit
-x list entries by lines instead of by columns
-X sort alphabetically by entry extension
-Z, --context print any security context of each file
-1 list one file per line. Avoid '\n' with -q or -b
--help display this help and exit
--version output version information and exit
The SIZE argument is an integer and optional unit (example: 10K is 10*1024).
Units are K,M,G,T,P,E,Z,Y (powers of 1024) or KB,MB,... (powers of 1000).
Binary prefixes can be used, too: KiB=K, MiB=M, and so on.
The TIME_STYLE argument can be full-iso, long-iso, iso, locale, or +FORMAT.
FORMAT is interpreted like in date(1). If FORMAT is FORMAT1<newline>FORMAT2,
then FORMAT1 applies to non-recent files and FORMAT2 to recent files.
TIME_STYLE prefixed with 'posix-' takes effect only outside the POSIX locale.
Also the TIME_STYLE environment variable sets the default style to use.
Using color to distinguish file types is disabled both by default and
with --color=never. With --color=auto, ls emits color codes only when
standard output is connected to a terminal. The LS_COLORS environment
variable can change the settings. Use the dircolors command to set it.
Exit status:
0 if OK,
1 if minor problems (e.g., cannot access subdirectory),
2 if serious trouble (e.g., cannot access command-line argument).
GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
Full documentation <https://www.gnu.org/software/coreutils/ls>
or available locally via: info '(coreutils) ls invocation'
md5sum
Compute and check MD5 message digest.
user $md5sum --helpUsage: md5sum [OPTION]... [FILE]...
Print or check MD5 (128-bit) checksums.
With no FILE, or when FILE is -, read standard input.
-b, --binary read in binary mode
-c, --check read MD5 sums from the FILEs and check them
--tag create a BSD-style checksum
-t, --text read in text mode (default)
-z, --zero end each output line with NUL, not newline,
and disable file name escaping
The following five options are useful only when verifying checksums:
--ignore-missing don't fail or report status for missing files
--quiet don't print OK for each successfully verified file
--status don't output anything, status code shows success
--strict exit non-zero for improperly formatted checksum lines
-w, --warn warn about improperly formatted checksum lines
--help display this help and exit
--version output version information and exit
The sums are computed as described in RFC 1321. When checking, the input
should be a former output of this program. The default mode is to print a
line with checksum, a space, a character indicating input mode ('*' for binary,
' ' for text or where binary is insignificant), and name for each FILE.
Note: There is no difference between binary mode and text mode on GNU systems.
GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
Full documentation <https://www.gnu.org/software/coreutils/md5sum>
or available locally via: info '(coreutils) md5sum invocation'
mkdir
Make directories.
user $mkdir --helpUsage: mkdir [OPTION]... DIRECTORY...
Create the DIRECTORY(ies), if they do not already exist.
Mandatory arguments to long options are mandatory for short options too.
-m, --mode=MODE set file mode (as in chmod), not a=rwx - umask
-p, --parents no error if existing, make parent directories as needed
-v, --verbose print a message for each created directory
-Z set SELinux security context of each created directory
to the default type
--context[=CTX] like -Z, or if CTX is specified then set the SELinux
or SMACK security context to CTX
--help display this help and exit
--version output version information and exit
GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
Full documentation <https://www.gnu.org/software/coreutils/mkdir>
or available locally via: info '(coreutils) mkdir invocation'
mkfifo
Make FIFOs (named pipes).
user $mkfifo --helpUsage: mkfifo [OPTION]... NAME...
Create named pipes (FIFOs) with the given NAMEs.
Mandatory arguments to long options are mandatory for short options too.
-m, --mode=MODE set file permission bits to MODE, not a=rw - umask
-Z set the SELinux security context to default type
--context[=CTX] like -Z, or if CTX is specified then set the SELinux
or SMACK security context to CTX
--help display this help and exit
--version output version information and exit
GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
Full documentation <https://www.gnu.org/software/coreutils/mkfifo>
or available locally via: info '(coreutils) mkfifo invocation'
mknod
Make block or character special files.
user $mknod --helpUsage: mknod [OPTION]... NAME TYPE [MAJOR MINOR]
Create the special file NAME of the given TYPE.
Mandatory arguments to long options are mandatory for short options too.
-m, --mode=MODE set file permission bits to MODE, not a=rw - umask
-Z set the SELinux security context to default type
--context[=CTX] like -Z, or if CTX is specified then set the SELinux
or SMACK security context to CTX
--help display this help and exit
--version output version information and exit
Both MAJOR and MINOR must be specified when TYPE is b, c, or u, and they
must be omitted when TYPE is p. If MAJOR or MINOR begins with 0x or 0X,
it is interpreted as hexadecimal; otherwise, if it begins with 0, as octal;
otherwise, as decimal. TYPE may be:
b create a block (buffered) special file
c, u create a character (unbuffered) special file
p create a FIFO
NOTE: your shell may have its own version of mknod, which usually supersedes
the version described here. Please refer to your shell's documentation
for details about the options it supports.
GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
Full documentation <https://www.gnu.org/software/coreutils/mknod>
or available locally via: info '(coreutils) mknod invocation'
mktemp
Create a temporary file or directory.
user $mktemp --helpUsage: mktemp [OPTION]... [TEMPLATE]
Create a temporary file or directory, safely, and print its name.
TEMPLATE must contain at least 3 consecutive 'X's in last component.
If TEMPLATE is not specified, use tmp.XXXXXXXXXX, and --tmpdir is implied.
Files are created u+rw, and directories u+rwx, minus umask restrictions.
-d, --directory create a directory, not a file
-u, --dry-run do not create anything; merely print a name (unsafe)
-q, --quiet suppress diagnostics about file/dir-creation failure
--suffix=SUFF append SUFF to TEMPLATE; SUFF must not contain a slash.
This option is implied if TEMPLATE does not end in X
-p DIR, --tmpdir[=DIR] interpret TEMPLATE relative to DIR; if DIR is not
specified, use $TMPDIR if set, else /tmp. With
this option, TEMPLATE must not be an absolute name;
unlike with -t, TEMPLATE may contain slashes, but
mktemp creates only the final component
-t interpret TEMPLATE as a single file name component,
relative to a directory: $TMPDIR, if set; else the
directory specified via -p; else /tmp [deprecated]
--help display this help and exit
--version output version information and exit
GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
Full documentation <https://www.gnu.org/software/coreutils/mktemp>
or available locally via: info '(coreutils) mktemp invocation'
mv
Move (rename) files.
user $mv --helpUsage: mv [OPTION]... [-T] SOURCE DEST
or: mv [OPTION]... SOURCE... DIRECTORY
or: mv [OPTION]... -t DIRECTORY SOURCE...
Rename SOURCE to DEST, or move SOURCE(s) to DIRECTORY.
Mandatory arguments to long options are mandatory for short options too.
--backup[=CONTROL] make a backup of each existing destination file
-b like --backup but does not accept an argument
-f, --force do not prompt before overwriting
-i, --interactive prompt before overwrite
-n, --no-clobber do not overwrite an existing file
If you specify more than one of -i, -f, -n, only the final one takes effect.
--strip-trailing-slashes remove any trailing slashes from each SOURCE
argument
-S, --suffix=SUFFIX override the usual backup suffix
-t, --target-directory=DIRECTORY move all SOURCE arguments into DIRECTORY
-T, --no-target-directory treat DEST as a normal file
-u, --update move only when the SOURCE file is newer
than the destination file or when the
destination file is missing
-v, --verbose explain what is being done
-Z, --context set SELinux security context of destination
file to default type
--help display this help and exit
--version output version information and exit
The backup suffix is '~', unless set with --suffix or SIMPLE_BACKUP_SUFFIX.
The version control method may be selected via the --backup option or through
the VERSION_CONTROL environment variable. Here are the values:
none, off never make backups (even if --backup is given)
numbered, t make numbered backups
existing, nil numbered if numbered backups exist, simple otherwise
simple, never always make simple backups
GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
Full documentation <https://www.gnu.org/software/coreutils/mv>
or available locally via: info '(coreutils) mv invocation'
nice
Run a program with modified scheduling priority.
user $nice --helpUsage: nice [OPTION] [COMMAND [ARG]...]
Run COMMAND with an adjusted niceness, which affects process scheduling.
With no COMMAND, print the current niceness. Niceness values range from
-20 (most favorable to the process) to 19 (least favorable to the process).
Mandatory arguments to long options are mandatory for short options too.
-n, --adjustment=N add integer N to the niceness (default 10)
--help display this help and exit
--version output version information and exit
NOTE: your shell may have its own version of nice, which usually supersedes
the version described here. Please refer to your shell's documentation
for details about the options it supports.
GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
Full documentation <https://www.gnu.org/software/coreutils/nice>
or available locally via: info '(coreutils) nice invocation'
nl
Number lines of files.
user $nl --helpUsage: nl [OPTION]... [FILE]...
Write each FILE to standard output, with line numbers added.
With no FILE, or when FILE is -, read standard input.
Mandatory arguments to long options are mandatory for short options too.
-b, --body-numbering=STYLE use STYLE for numbering body lines
-d, --section-delimiter=CC use CC for logical page delimiters
-f, --footer-numbering=STYLE use STYLE for numbering footer lines
-h, --header-numbering=STYLE use STYLE for numbering header lines
-i, --line-increment=NUMBER line number increment at each line
-l, --join-blank-lines=NUMBER group of NUMBER empty lines counted as one
-n, --number-format=FORMAT insert line numbers according to FORMAT
-p, --no-renumber do not reset line numbers for each section
-s, --number-separator=STRING add STRING after (possible) line number
-v, --starting-line-number=NUMBER first line number for each section
-w, --number-width=NUMBER use NUMBER columns for line numbers
--help display this help and exit
--version output version information and exit
Default options are: -bt -d'\:' -fn -hn -i1 -l1 -n'rn' -s<TAB> -v1 -w6
CC are two delimiter characters used to construct logical page delimiters;
a missing second character implies ':'.
STYLE is one of:
a number all lines
t number only nonempty lines
n number no lines
pBRE number only lines that contain a match for the basic regular
expression, BRE
FORMAT is one of:
ln left justified, no leading zeros
rn right justified, no leading zeros
rz right justified, leading zeros
GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
Full documentation <https://www.gnu.org/software/coreutils/nl>
or available locally via: info '(coreutils) nl invocation'
nohup
Run a command immune to hangups, with output to a non-tty.
user $nohup --helpUsage: nohup COMMAND [ARG]...
or: nohup OPTION
Run COMMAND, ignoring hangup signals.
--help display this help and exit
--version output version information and exit
If standard input is a terminal, redirect it from an unreadable file.
If standard output is a terminal, append output to 'nohup.out' if possible,
'$HOME/nohup.out' otherwise.
If standard error is a terminal, redirect it to standard output.
To save output to FILE, use 'nohup COMMAND > FILE'.
NOTE: your shell may have its own version of nohup, which usually supersedes
the version described here. Please refer to your shell's documentation
for details about the options it supports.
GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
Full documentation <https://www.gnu.org/software/coreutils/nohup>
or available locally via: info '(coreutils) nohup invocation'
nproc
Print the number of processing units available.
user $nproc --helpUsage: nproc [OPTION]...
Print the number of processing units available to the current process,
which may be less than the number of online processors
--all print the number of installed processors
--ignore=N if possible, exclude N processing units
--help display this help and exit
--version output version information and exit
GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
Full documentation <https://www.gnu.org/software/coreutils/nproc>
or available locally via: info '(coreutils) nproc invocation'
numfmt
Convert numbers from/to human-readable strings.
user $numfmt --helpUsage: numfmt [OPTION]... [NUMBER]...
Reformat NUMBER(s), or the numbers from standard input if none are specified.
Mandatory arguments to long options are mandatory for short options too.
--debug print warnings about invalid input
-d, --delimiter=X use X instead of whitespace for field delimiter
--field=FIELDS replace the numbers in these input fields (default=1)
see FIELDS below
--format=FORMAT use printf style floating-point FORMAT;
see FORMAT below for details
--from=UNIT auto-scale input numbers to UNITs; default is 'none';
see UNIT below
--from-unit=N specify the input unit size (instead of the default 1)
--grouping use locale-defined grouping of digits, e.g. 1,000,000
(which means it has no effect in the C/POSIX locale)
--header[=N] print (without converting) the first N header lines;
N defaults to 1 if not specified
--invalid=MODE failure mode for invalid numbers: MODE can be:
abort (default), fail, warn, ignore
--padding=N pad the output to N characters; positive N will
right-align; negative N will left-align;
padding is ignored if the output is wider than N;
the default is to automatically pad if a whitespace
is found
--round=METHOD use METHOD for rounding when scaling; METHOD can be:
up, down, from-zero (default), towards-zero, nearest
--suffix=SUFFIX add SUFFIX to output numbers, and accept optional
SUFFIX in input numbers
--to=UNIT auto-scale output numbers to UNITs; see UNIT below
--to-unit=N the output unit size (instead of the default 1)
-z, --zero-terminated line delimiter is NUL, not newline
--help display this help and exit
--version output version information and exit
UNIT options:
none no auto-scaling is done; suffixes will trigger an error
auto accept optional single/two letter suffix:
1K = 1000,
1Ki = 1024,
1M = 1000000,
1Mi = 1048576,
si accept optional single letter suffix:
1K = 1000,
1M = 1000000,
...
iec accept optional single letter suffix:
1K = 1024,
1M = 1048576,
...
iec-i accept optional two-letter suffix:
1Ki = 1024,
1Mi = 1048576,
...
FIELDS supports cut(1) style field ranges:
N N'th field, counted from 1
N- from N'th field, to end of line
N-M from N'th to M'th field (inclusive)
-M from first to M'th field (inclusive)
- all fields
Multiple fields/ranges can be separated with commas
FORMAT must be suitable for printing one floating-point argument '%f'.
Optional quote (%'f) will enable --grouping (if supported by current locale).
Optional width value (%10f) will pad output. Optional zero (%010f) width
will zero pad the number. Optional negative values (%-10f) will left align.
Optional precision (%.1f) will override the input determined precision.
Exit status is 0 if all input numbers were successfully converted.
By default, numfmt will stop at the first conversion error with exit status 2.
With --invalid='fail' a warning is printed for each conversion error
and the exit status is 2. With --invalid='warn' each conversion error is
diagnosed, but the exit status is 0. With --invalid='ignore' conversion
errors are not diagnosed and the exit status is 0.
Examples:
$ numfmt --to=si 1000
-> "1.0K"
$ numfmt --to=iec 2048
-> "2.0K"
$ numfmt --to=iec-i 4096
-> "4.0Ki"
$ echo 1K | numfmt --from=si
-> "1000"
$ echo 1K | numfmt --from=iec
-> "1024"
$ df -B1 | numfmt --header --field 2-4 --to=si
$ ls -l | numfmt --header --field 5 --to=iec
$ ls -lh | numfmt --header --field 5 --from=iec --padding=10
$ ls -lh | numfmt --header --field 5 --from=iec --format %10f
GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
Full documentation <https://www.gnu.org/software/coreutils/numfmt>
or available locally via: info '(coreutils) numfmt invocation'
od
Dump files in octal and other formats.
user $od --helpUsage: od [OPTION]... [FILE]...
or: od [-abcdfilosx]... [FILE] [[+]OFFSET[.][b]]
or: od --traditional [OPTION]... [FILE] [[+]OFFSET[.][b] [+][LABEL][.][b]]
Write an unambiguous representation, octal bytes by default,
of FILE to standard output. With more than one FILE argument,
concatenate them in the listed order to form the input.
With no FILE, or when FILE is -, read standard input.
If first and second call formats both apply, the second format is assumed
if the last operand begins with + or (if there are 2 operands) a digit.
An OFFSET operand means -j OFFSET. LABEL is the pseudo-address
at first byte printed, incremented when dump is progressing.
For OFFSET and LABEL, a 0x or 0X prefix indicates hexadecimal;
suffixes may be . for octal and b for multiply by 512.
Mandatory arguments to long options are mandatory for short options too.
-A, --address-radix=RADIX output format for file offsets; RADIX is one
of [doxn], for Decimal, Octal, Hex or None
--endian={big|little} swap input bytes according the specified order
-j, --skip-bytes=BYTES skip BYTES input bytes first
-N, --read-bytes=BYTES limit dump to BYTES input bytes
-S BYTES, --strings[=BYTES] output strings of at least BYTES graphic chars;
3 is implied when BYTES is not specified
-t, --format=TYPE select output format or formats
-v, --output-duplicates do not use * to mark line suppression
-w[BYTES], --width[=BYTES] output BYTES bytes per output line;
32 is implied when BYTES is not specified
--traditional accept arguments in third form above
--help display this help and exit
--version output version information and exit
Traditional format specifications may be intermixed; they accumulate:
-a same as -t a, select named characters, ignoring high-order bit
-b same as -t o1, select octal bytes
-c same as -t c, select printable characters or backslash escapes
-d same as -t u2, select unsigned decimal 2-byte units
-f same as -t fF, select floats
-i same as -t dI, select decimal ints
-l same as -t dL, select decimal longs
-o same as -t o2, select octal 2-byte units
-s same as -t d2, select decimal 2-byte units
-x same as -t x2, select hexadecimal 2-byte units
TYPE is made up of one or more of these specifications:
a named character, ignoring high-order bit
c printable character or backslash escape
d[SIZE] signed decimal, SIZE bytes per integer
f[SIZE] floating point, SIZE bytes per float
o[SIZE] octal, SIZE bytes per integer
u[SIZE] unsigned decimal, SIZE bytes per integer
x[SIZE] hexadecimal, SIZE bytes per integer
SIZE is a number. For TYPE in [doux], SIZE may also be C for
sizeof(char), S for sizeof(short), I for sizeof(int) or L for
sizeof(long). If TYPE is f, SIZE may also be F for sizeof(float), D
for sizeof(double) or L for sizeof(long double).
Adding a z suffix to any type displays printable characters at the end of
each output line.
BYTES is hex with 0x or 0X prefix, and may have a multiplier suffix:
b 512
KB 1000
K 1024
MB 1000*1000
M 1024*1024
and so on for G, T, P, E, Z, Y.
Binary prefixes can be used, too: KiB=K, MiB=M, and so on.
GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
Full documentation <https://www.gnu.org/software/coreutils/od>
or available locally via: info '(coreutils) od invocation'
paste
Merge lines of files.
user $paste --helpUsage: paste [OPTION]... [FILE]...
Write lines consisting of the sequentially corresponding lines from
each FILE, separated by TABs, to standard output.
With no FILE, or when FILE is -, read standard input.
Mandatory arguments to long options are mandatory for short options too.
-d, --delimiters=LIST reuse characters from LIST instead of TABs
-s, --serial paste one file at a time instead of in parallel
-z, --zero-terminated line delimiter is NUL, not newline
--help display this help and exit
--version output version information and exit
GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
Full documentation <https://www.gnu.org/software/coreutils/paste>
or available locally via: info '(coreutils) paste invocation'
pathchk
Check whether file names are valid or portable.
user $pathchk --helpUsage: pathchk [OPTION]... NAME...
Diagnose invalid or unportable file names.
-p check for most POSIX systems
-P check for empty names and leading "-"
--portability check for all POSIX systems (equivalent to -p -P)
--help display this help and exit
--version output version information and exit
GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
Full documentation <https://www.gnu.org/software/coreutils/pathchk>
or available locally via: info '(coreutils) pathchk invocation'
pinky
Lightweight finger. Print user informtion.
user $pinky --helpUsage: pinky [OPTION]... [USER]...
-l produce long format output for the specified USERs
-b omit the user's home directory and shell in long format
-h omit the user's project file in long format
-p omit the user's plan file in long format
-s do short format output, this is the default
-f omit the line of column headings in short format
-w omit the user's full name in short format
-i omit the user's full name and remote host in short format
-q omit the user's full name, remote host and idle time
in short format
--help display this help and exit
--version output version information and exit
A lightweight 'finger' program; print user information.
The utmp file will be /var/run/utmp.
GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
Full documentation <https://www.gnu.org/software/coreutils/pinky>
or available locally via: info '(coreutils) pinky invocation'
pr
Convert text files for printing.
user $pr --helpUsage: pr [OPTION]... [FILE]...
Paginate or columnate FILE(s) for printing.
With no FILE, or when FILE is -, read standard input.
Mandatory arguments to long options are mandatory for short options too.
+FIRST_PAGE[:LAST_PAGE], --pages=FIRST_PAGE[:LAST_PAGE]
begin [stop] printing with page FIRST_[LAST_]PAGE
-COLUMN, --columns=COLUMN
output COLUMN columns and print columns down,
unless -a is used. Balance number of lines in the
columns on each page
-a, --across print columns across rather than down, used together
with -COLUMN
-c, --show-control-chars
use hat notation (^G) and octal backslash notation
-d, --double-space
double space the output
-D, --date-format=FORMAT
use FORMAT for the header date
-e[CHAR[WIDTH]], --expand-tabs[=CHAR[WIDTH]]
expand input CHARs (TABs) to tab WIDTH (8)
-F, -f, --form-feed
use form feeds instead of newlines to separate pages
(by a 3-line page header with -F or a 5-line header
and trailer without -F)
-h, --header=HEADER
use a centered HEADER instead of filename in page header,
-h "" prints a blank line, don't use -h""
-i[CHAR[WIDTH]], --output-tabs[=CHAR[WIDTH]]
replace spaces with CHARs (TABs) to tab WIDTH (8)
-J, --join-lines merge full lines, turns off -W line truncation, no column
alignment, --sep-string[=STRING] sets separators
-l, --length=PAGE_LENGTH
set the page length to PAGE_LENGTH (66) lines
(default number of lines of text 56, and with -F 63).
implies -t if PAGE_LENGTH <= 10
-m, --merge print all files in parallel, one in each column,
truncate lines, but join lines of full length with -J
-n[SEP[DIGITS]], --number-lines[=SEP[DIGITS]]
number lines, use DIGITS (5) digits, then SEP (TAB),
default counting starts with 1st line of input file
-N, --first-line-number=NUMBER
start counting with NUMBER at 1st line of first
page printed (see +FIRST_PAGE)
-o, --indent=MARGIN
offset each line with MARGIN (zero) spaces, do not
affect -w or -W, MARGIN will be added to PAGE_WIDTH
-r, --no-file-warnings
omit warning when a file cannot be opened
-s[CHAR], --separator[=CHAR]
separate columns by a single character, default for CHAR
is the <TAB> character without -w and 'no char' with -w.
-s[CHAR] turns off line truncation of all 3 column
options (-COLUMN|-a -COLUMN|-m) except -w is set
-S[STRING], --sep-string[=STRING]
separate columns by STRING,
without -S: Default separator <TAB> with -J and <space>
otherwise (same as -S" "), no effect on column options
-t, --omit-header omit page headers and trailers;
implied if PAGE_LENGTH <= 10
-T, --omit-pagination
omit page headers and trailers, eliminate any pagination
by form feeds set in input files
-v, --show-nonprinting
use octal backslash notation
-w, --width=PAGE_WIDTH
set page width to PAGE_WIDTH (72) characters for
multiple text-column output only, -s[char] turns off (72)
-W, --page-width=PAGE_WIDTH
set page width to PAGE_WIDTH (72) characters always,
truncate lines, except -J option is set, no interference
with -S or -s
--help display this help and exit
--version output version information and exit
GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
Full documentation <https://www.gnu.org/software/coreutils/pr>
or available locally via: info '(coreutils) pr invocation'
printenv
Print all or part of environment.
user $printenv --helpUsage: printenv [OPTION]... [VARIABLE]...
Print the values of the specified environment VARIABLE(s).
If no VARIABLE is specified, print name and value pairs for them all.
-0, --null end each output line with NUL, not newline
--help display this help and exit
--version output version information and exit
NOTE: your shell may have its own version of printenv, which usually supersedes
the version described here. Please refer to your shell's documentation
for details about the options it supports.
GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
Full documentation <https://www.gnu.org/software/coreutils/printenv>
or available locally via: info '(coreutils) printenv invocation'
printf
Display text according to a format string.
user $/usr/bin/printf --helpUsage: /usr/bin/printf FORMAT [ARGUMENT]...
or: /usr/bin/printf OPTION
Print ARGUMENT(s) according to FORMAT, or execute according to OPTION:
--help display this help and exit
--version output version information and exit
FORMAT controls the output as in C printf. Interpreted sequences are:
\" double quote
\\ backslash
\a alert (BEL)
\b backspace
\c produce no further output
\e escape
\f form feed
\n new line
\r carriage return
\t horizontal tab
\v vertical tab
\NNN byte with octal value NNN (1 to 3 digits)
\xHH byte with hexadecimal value HH (1 to 2 digits)
\uHHHH Unicode (ISO/IEC 10646) character with hex value HHHH (4 digits)
\UHHHHHHHH Unicode character with hex value HHHHHHHH (8 digits)
%% a single %
%b ARGUMENT as a string with '\' escapes interpreted,
except that octal escapes are of the form \0 or \0NNN
%q ARGUMENT is printed in a format that can be reused as shell input,
escaping non-printable characters with the proposed POSIX $'' syntax.
and all C format specifications ending with one of diouxXfeEgGcs, with
ARGUMENTs converted to proper type first. Variable widths are handled.
NOTE: your shell may have its own version of printf, which usually supersedes
the version described here. Please refer to your shell's documentation
for details about the options it supports.
GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
Full documentation <https://www.gnu.org/software/coreutils/printf>
or available locally via: info '(coreutils) printf invocation'n.b. Some shells have a printf command built in, which is why this needs the /usr/bin prefix to return the help text.
ptx
Produce a permuted index of file contents.
user $ptx --helpUsage: ptx [OPTION]... [INPUT]... (without -G)
or: ptx -G [OPTION]... [INPUT [OUTPUT]]
Output a permuted index, including context, of the words in the input files.
With no FILE, or when FILE is -, read standard input.
Mandatory arguments to long options are mandatory for short options too.
-A, --auto-reference output automatically generated references
-G, --traditional behave more like System V 'ptx'
-F, --flag-truncation=STRING use STRING for flagging line truncations.
The default is '/'
-M, --macro-name=STRING macro name to use instead of 'xx'
-O, --format=roff generate output as roff directives
-R, --right-side-refs put references at right, not counted in -w
-S, --sentence-regexp=REGEXP for end of lines or end of sentences
-T, --format=tex generate output as TeX directives
-W, --word-regexp=REGEXP use REGEXP to match each keyword
-b, --break-file=FILE word break characters in this FILE
-f, --ignore-case fold lower case to upper case for sorting
-g, --gap-size=NUMBER gap size in columns between output fields
-i, --ignore-file=FILE read ignore word list from FILE
-o, --only-file=FILE read only word list from this FILE
-r, --references first field of each line is a reference
-t, --typeset-mode - not implemented -
-w, --width=NUMBER output width in columns, reference excluded
--help display this help and exit
--version output version information and exit
GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
Full documentation <https://www.gnu.org/software/coreutils/ptx>
or available locally via: info '(coreutils) ptx invocation'
pwd
Output the current working directory.
user $pwd --helpUsage: /bin/pwd [OPTION]...
Print the full filename of the current working directory.
-L, --logical use PWD from environment, even if it contains symlinks
-P, --physical avoid all symlinks
--help display this help and exit
--version output version information and exit
If no option is specified, -P is assumed.
NOTE: your shell may have its own version of pwd, which usually supersedes
the version described here. Please refer to your shell's documentation
for details about the options it supports.
GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
Full documentation <https://www.gnu.org/software/coreutils/pwd>
or available locally via: info '(coreutils) pwd invocation'
n.b. Some shells have a pwd builtin, which is why this needs the /bin prefix to return the help text.
readlink
Print resolved symbolic links or canonical file names.
user $readlink --helpUsage: readlink [OPTION]... FILE...
Print value of a symbolic link or canonical file name
-f, --canonicalize canonicalize by following every symlink in
every component of the given name recursively;
all but the last component must exist
-e, --canonicalize-existing canonicalize by following every symlink in
every component of the given name recursively,
all components must exist
-m, --canonicalize-missing canonicalize by following every symlink in
every component of the given name recursively,
without requirements on components existence
-n, --no-newline do not output the trailing delimiter
-q, --quiet
-s, --silent suppress most error messages (on by default)
-v, --verbose report error messages
-z, --zero end each output line with NUL, not newline
--help display this help and exit
--version output version information and exit
GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
Full documentation <https://www.gnu.org/software/coreutils/readlink>
or available locally via: info '(coreutils) readlink invocation'
realpath
Print the resolved path.
user $realpath --helpUsage: realpath [OPTION]... FILE...
Print the resolved absolute file name;
all but the last component must exist
-e, --canonicalize-existing all components of the path must exist
-m, --canonicalize-missing no path components need exist or be a directory
-L, --logical resolve '..' components before symlinks
-P, --physical resolve symlinks as encountered (default)
-q, --quiet suppress most error messages
--relative-to=DIR print the resolved path relative to DIR
--relative-base=DIR print absolute paths unless paths below DIR
-s, --strip, --no-symlinks don't expand symlinks
-z, --zero end each output line with NUL, not newline
--help display this help and exit
--version output version information and exit
GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
Full documentation <https://www.gnu.org/software/coreutils/realpath>
or available locally via: info '(coreutils) realpath invocation'
rm
Remove files or directories.
user $rm --helpUsage: /bin/rm [OPTION]... [FILE]...
Remove (unlink) the FILE(s).
-f, --force ignore nonexistent files and arguments, never prompt
-i prompt before every removal
-I prompt once before removing more than three files, or
when removing recursively; less intrusive than -i,
while still giving protection against most mistakes
--interactive[=WHEN] prompt according to WHEN: never, once (-I), or
always (-i); without WHEN, prompt always
--one-file-system when removing a hierarchy recursively, skip any
directory that is on a file system different from
that of the corresponding command line argument
--no-preserve-root do not treat '/' specially
--preserve-root[=all] do not remove '/' (default);
with 'all', reject any command line argument
on a separate device from its parent
-r, -R, --recursive remove directories and their contents recursively
-d, --dir remove empty directories
-v, --verbose explain what is being done
--help display this help and exit
--version output version information and exit
By default, rm does not remove directories. Use the --recursive (-r or -R)
option to remove each listed directory, too, along with all of its contents.
To remove a file whose name starts with a '-', for example '-foo',
use one of these commands:
/bin/rm -- -foo
/bin/rm ./-foo
Note that if you use rm to remove a file, it might be possible to recover
some of its contents, given sufficient expertise and/or time. For greater
assurance that the contents are truly unrecoverable, consider using shred.
GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
Full documentation <https://www.gnu.org/software/coreutils/rm>
or available locally via: info '(coreutils) rm invocation'
Warning
The rm command is irrevocable. The --recursive option can induce massive data loss if used carelessly.
The rm command is irrevocable. The --recursive option can induce massive data loss if used carelessly.
rmdir
Remove empty directories.
user $rmdir --helpUsage: rmdir [OPTION]... DIRECTORY...
Remove the DIRECTORY(ies), if they are empty.
--ignore-fail-on-non-empty
ignore each failure that is solely because a directory
is non-empty
-p, --parents remove DIRECTORY and its ancestors; e.g., 'rmdir -p a/b/c' is
similar to 'rmdir a/b/c a/b a'
-v, --verbose output a diagnostic for every directory processed
--help display this help and exit
--version output version information and exit
GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
Full documentation <https://www.gnu.org/software/coreutils/rmdir>
or available locally via: info '(coreutils) rmdir invocation'
Warning
The rmdir command is irrevocable. It can induce massive data loss if used carelessly.
The rmdir command is irrevocable. It can induce massive data loss if used carelessly.
runcon
Run command with specified security context.
user $runcon --helpUsage: runcon CONTEXT COMMAND [args]
or: runcon [ -c ] [-u USER] [-r ROLE] [-t TYPE] [-l RANGE] COMMAND [args]
Run a program in a different SELinux security context.
With neither CONTEXT nor COMMAND, print the current security context.
Mandatory arguments to long options are mandatory for short options too.
CONTEXT Complete security context
-c, --compute compute process transition context before modifying
-t, --type=TYPE type (for same role as parent)
-u, --user=USER user identity
-r, --role=ROLE role
-l, --range=RANGE levelrange
--help display this help and exit
--version output version information and exit
GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
Full documentation <https://www.gnu.org/software/coreutils/runcon>
or available locally via: info '(coreutils) runcon invocation'
seq
Print a sequence of numbers.
user $seq --helpUsage: seq [OPTION]... LAST
or: seq [OPTION]... FIRST LAST
or: seq [OPTION]... FIRST INCREMENT LAST
Print numbers from FIRST to LAST, in steps of INCREMENT.
Mandatory arguments to long options are mandatory for short options too.
-f, --format=FORMAT use printf style floating-point FORMAT
-s, --separator=STRING use STRING to separate numbers (default: \n)
-w, --equal-width equalize width by padding with leading zeroes
--help display this help and exit
--version output version information and exit
If FIRST or INCREMENT is omitted, it defaults to 1. That is, an
omitted INCREMENT defaults to 1 even when LAST is smaller than FIRST.
The sequence of numbers ends when the sum of the current number and
INCREMENT would become greater than LAST.
FIRST, INCREMENT, and LAST are interpreted as floating point values.
INCREMENT is usually positive if FIRST is smaller than LAST, and
INCREMENT is usually negative if FIRST is greater than LAST.
INCREMENT must not be 0; none of FIRST, INCREMENT and LAST may be NaN.
FORMAT must be suitable for printing one argument of type 'double';
it defaults to %.PRECf if FIRST, INCREMENT, and LAST are all fixed point
decimal numbers with maximum precision PREC, and to %g otherwise.
GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
Full documentation <https://www.gnu.org/software/coreutils/seq>
or available locally via: info '(coreutils) seq invocation'
sha1sum
Compute and check SHA1 message digest.
user $sha1sum --helpUsage: sha1sum [OPTION]... [FILE]...
Print or check SHA1 (160-bit) checksums.
With no FILE, or when FILE is -, read standard input.
-b, --binary read in binary mode
-c, --check read SHA1 sums from the FILEs and check them
--tag create a BSD-style checksum
-t, --text read in text mode (default)
-z, --zero end each output line with NUL, not newline,
and disable file name escaping
The following five options are useful only when verifying checksums:
--ignore-missing don't fail or report status for missing files
--quiet don't print OK for each successfully verified file
--status don't output anything, status code shows success
--strict exit non-zero for improperly formatted checksum lines
-w, --warn warn about improperly formatted checksum lines
--help display this help and exit
--version output version information and exit
The sums are computed as described in FIPS-180-1. When checking, the input
should be a former output of this program. The default mode is to print a
line with checksum, a space, a character indicating input mode ('*' for binary,
' ' for text or where binary is insignificant), and name for each FILE.
Note: There is no difference between binary mode and text mode on GNU systems.
GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
Full documentation <https://www.gnu.org/software/coreutils/sha1sum>
or available locally via: info '(coreutils) sha1sum invocation'
sha224sum
Compute and check SHA224 message digest.
user $sha224sum --helpUsage: sha224sum [OPTION]... [FILE]...
Print or check SHA224 (224-bit) checksums.
With no FILE, or when FILE is -, read standard input.
-b, --binary read in binary mode
-c, --check read SHA224 sums from the FILEs and check them
--tag create a BSD-style checksum
-t, --text read in text mode (default)
-z, --zero end each output line with NUL, not newline,
and disable file name escaping
The following five options are useful only when verifying checksums:
--ignore-missing don't fail or report status for missing files
--quiet don't print OK for each successfully verified file
--status don't output anything, status code shows success
--strict exit non-zero for improperly formatted checksum lines
-w, --warn warn about improperly formatted checksum lines
--help display this help and exit
--version output version information and exit
The sums are computed as described in RFC 3874. When checking, the input
should be a former output of this program. The default mode is to print a
line with checksum, a space, a character indicating input mode ('*' for binary,
' ' for text or where binary is insignificant), and name for each FILE.
Note: There is no difference between binary mode and text mode on GNU systems.
GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
Full documentation <https://www.gnu.org/software/coreutils/sha224sum>
or available locally via: info '(coreutils) sha2 utilities'
sha256sum
Compute and check SHA256 message digest.
user $sha256sum --helpUsage: sha256sum [OPTION]... [FILE]...
Print or check SHA256 (256-bit) checksums.
With no FILE, or when FILE is -, read standard input.
-b, --binary read in binary mode
-c, --check read SHA256 sums from the FILEs and check them
--tag create a BSD-style checksum
-t, --text read in text mode (default)
-z, --zero end each output line with NUL, not newline,
and disable file name escaping
The following five options are useful only when verifying checksums:
--ignore-missing don't fail or report status for missing files
--quiet don't print OK for each successfully verified file
--status don't output anything, status code shows success
--strict exit non-zero for improperly formatted checksum lines
-w, --warn warn about improperly formatted checksum lines
--help display this help and exit
--version output version information and exit
The sums are computed as described in FIPS-180-2. When checking, the input
should be a former output of this program. The default mode is to print a
line with checksum, a space, a character indicating input mode ('*' for binary,
' ' for text or where binary is insignificant), and name for each FILE.
Note: There is no difference between binary mode and text mode on GNU systems.
GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
Full documentation <https://www.gnu.org/software/coreutils/sha256sum>
or available locally via: info '(coreutils) sha2 utilities'
sha384sum
Compute and check SHA384 message digest.
user $sha384sum --helpUsage: sha384sum [OPTION]... [FILE]...
Print or check SHA384 (384-bit) checksums.
With no FILE, or when FILE is -, read standard input.
-b, --binary read in binary mode
-c, --check read SHA384 sums from the FILEs and check them
--tag create a BSD-style checksum
-t, --text read in text mode (default)
-z, --zero end each output line with NUL, not newline,
and disable file name escaping
The following five options are useful only when verifying checksums:
--ignore-missing don't fail or report status for missing files
--quiet don't print OK for each successfully verified file
--status don't output anything, status code shows success
--strict exit non-zero for improperly formatted checksum lines
-w, --warn warn about improperly formatted checksum lines
--help display this help and exit
--version output version information and exit
The sums are computed as described in FIPS-180-2. When checking, the input
should be a former output of this program. The default mode is to print a
line with checksum, a space, a character indicating input mode ('*' for binary,
' ' for text or where binary is insignificant), and name for each FILE.
Note: There is no difference between binary mode and text mode on GNU systems.
GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
Full documentation <https://www.gnu.org/software/coreutils/sha384sum>
or available locally via: info '(coreutils) sha2 utilities'
sha512sum
Compute and check SHA512 message digest.
user $sha512sum --helpUsage: sha512sum [OPTION]... [FILE]...
Print or check SHA512 (512-bit) checksums.
With no FILE, or when FILE is -, read standard input.
-b, --binary read in binary mode
-c, --check read SHA512 sums from the FILEs and check them
--tag create a BSD-style checksum
-t, --text read in text mode (default)
-z, --zero end each output line with NUL, not newline,
and disable file name escaping
The following five options are useful only when verifying checksums:
--ignore-missing don't fail or report status for missing files
--quiet don't print OK for each successfully verified file
--status don't output anything, status code shows success
--strict exit non-zero for improperly formatted checksum lines
-w, --warn warn about improperly formatted checksum lines
--help display this help and exit
--version output version information and exit
The sums are computed as described in FIPS-180-2. When checking, the input
should be a former output of this program. The default mode is to print a
line with checksum, a space, a character indicating input mode ('*' for binary,
' ' for text or where binary is insignificant), and name for each FILE.
Note: There is no difference between binary mode and text mode on GNU systems.
GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
Full documentation <https://www.gnu.org/software/coreutils/sha512sum>
or available locally via: info '(coreutils) sha2 utilities'
shred
Overwrite a file to hide its contents, and optionally delete it.
user $shred --helpUsage: shred [OPTION]... FILE...
Overwrite the specified FILE(s) repeatedly, in order to make it harder
for even very expensive hardware probing to recover the data.
If FILE is -, shred standard output.
Mandatory arguments to long options are mandatory for short options too.
-f, --force change permissions to allow writing if necessary
-n, --iterations=N overwrite N times instead of the default (3)
--random-source=FILE get random bytes from FILE
-s, --size=N shred this many bytes (suffixes like K, M, G accepted)
-u deallocate and remove file after overwriting
--remove[=HOW] like -u but give control on HOW to delete; See below
-v, --verbose show progress
-x, --exact do not round file sizes up to the next full block;
this is the default for non-regular files
-z, --zero add a final overwrite with zeros to hide shredding
--help display this help and exit
--version output version information and exit
Delete FILE(s) if --remove (-u) is specified. The default is not to remove
the files because it is common to operate on device files like /dev/hda,
and those files usually should not be removed.
The optional HOW parameter indicates how to remove a directory entry:
'unlink' => use a standard unlink call.
'wipe' => also first obfuscate bytes in the name.
'wipesync' => also sync each obfuscated byte to disk.
The default mode is 'wipesync', but note it can be expensive.
CAUTION: shred assumes the file system and hardware overwrite data in place.
Although this is common, many platforms operate otherwise. Also, backups
and mirrors may contain unremovable copies that will let a shredded file
be recovered later. See the GNU coreutils manual for details.
GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
Full documentation <https://www.gnu.org/software/coreutils/shred>
or available locally via: info '(coreutils) shred invocation'
Warning
Of course the shred command will result in permanent data loss - by design.
Of course the shred command will result in permanent data loss - by design.
shuf
Generate random permutations.
user $shuf --helpUsage: shuf [OPTION]... [FILE]
or: shuf -e [OPTION]... [ARG]...
or: shuf -i LO-HI [OPTION]...
Write a random permutation of the input lines to standard output.
With no FILE, or when FILE is -, read standard input.
Mandatory arguments to long options are mandatory for short options too.
-e, --echo treat each ARG as an input line
-i, --input-range=LO-HI treat each number LO through HI as an input line
-n, --head-count=COUNT output at most COUNT lines
-o, --output=FILE write result to FILE instead of standard output
--random-source=FILE get random bytes from FILE
-r, --repeat output lines can be repeated
-z, --zero-terminated line delimiter is NUL, not newline
--help display this help and exit
--version output version information and exit
GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
Full documentation <https://www.gnu.org/software/coreutils/shuf>
or available locally via: info '(coreutils) shuf invocation'
sleep
Delay for a specified amount of time.
user $sleep --helpUsage: sleep NUMBER[SUFFIX]...
or: sleep OPTION
Pause for NUMBER seconds. SUFFIX may be 's' for seconds (the default),
'm' for minutes, 'h' for hours or 'd' for days. NUMBER need not be an
integer. Given two or more arguments, pause for the amount of time
specified by the sum of their values.
--help display this help and exit
--version output version information and exit
GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
Full documentation <https://www.gnu.org/software/coreutils/sleep>
or available locally via: info '(coreutils) sleep invocation'
sort
Sort lines of text files.
user $sort --helpUsage: sort [OPTION]... [FILE]...
or: sort [OPTION]... --files0-from=F
Write sorted concatenation of all FILE(s) to standard output.
With no FILE, or when FILE is -, read standard input.
Mandatory arguments to long options are mandatory for short options too.
Ordering options:
-b, --ignore-leading-blanks ignore leading blanks
-d, --dictionary-order consider only blanks and alphanumeric characters
-f, --ignore-case fold lower case to upper case characters
-g, --general-numeric-sort compare according to general numerical value
-i, --ignore-nonprinting consider only printable characters
-M, --month-sort compare (unknown) < 'JAN' < ... < 'DEC'
-h, --human-numeric-sort compare human readable numbers (e.g., 2K 1G)
-n, --numeric-sort compare according to string numerical value
-R, --random-sort shuffle, but group identical keys. See shuf(1)
--random-source=FILE get random bytes from FILE
-r, --reverse reverse the result of comparisons
--sort=WORD sort according to WORD:
general-numeric -g, human-numeric -h, month -M,
numeric -n, random -R, version -V
-V, --version-sort natural sort of (version) numbers within text
Other options:
--batch-size=NMERGE merge at most NMERGE inputs at once;
for more use temp files
-c, --check, --check=diagnose-first check for sorted input; do not sort
-C, --check=quiet, --check=silent like -c, but do not report first bad line
--compress-program=PROG compress temporaries with PROG;
decompress them with PROG -d
--debug annotate the part of the line used to sort,
and warn about questionable usage to stderr
--files0-from=F read input from the files specified by
NUL-terminated names in file F;
If F is - then read names from standard input
-k, --key=KEYDEF sort via a key; KEYDEF gives location and type
-m, --merge merge already sorted files; do not sort
-o, --output=FILE write result to FILE instead of standard output
-s, --stable stabilize sort by disabling last-resort comparison
-S, --buffer-size=SIZE use SIZE for main memory buffer
-t, --field-separator=SEP use SEP instead of non-blank to blank transition
-T, --temporary-directory=DIR use DIR for temporaries, not $TMPDIR or /tmp;
multiple options specify multiple directories
--parallel=N change the number of sorts run concurrently to N
-u, --unique with -c, check for strict ordering;
without -c, output only the first of an equal run
-z, --zero-terminated line delimiter is NUL, not newline
--help display this help and exit
--version output version information and exit
KEYDEF is F[.C][OPTS][,F[.C][OPTS]] for start and stop position, where F is a
field number and C a character position in the field; both are origin 1, and
the stop position defaults to the line's end. If neither -t nor -b is in
effect, characters in a field are counted from the beginning of the preceding
whitespace. OPTS is one or more single-letter ordering options [bdfgiMhnRrV],
which override global ordering options for that key. If no key is given, use
the entire line as the key. Use --debug to diagnose incorrect key usage.
SIZE may be followed by the following multiplicative suffixes:
% 1% of memory, b 1, K 1024 (default), and so on for M, G, T, P, E, Z, Y.
*** WARNING ***
The locale specified by the environment affects sort order.
Set LC_ALL=C to get the traditional sort order that uses
native byte values.
GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
Full documentation <https://www.gnu.org/software/coreutils/sort>
or available locally via: info '(coreutils) sort invocation'
split
Split a file into pieces.
user $split --helpUsage: split [OPTION]... [FILE [PREFIX]]
Output pieces of FILE to PREFIXaa, PREFIXab, ...;
default size is 1000 lines, and default PREFIX is 'x'.
With no FILE, or when FILE is -, read standard input.
Mandatory arguments to long options are mandatory for short options too.
-a, --suffix-length=N generate suffixes of length N (default 2)
--additional-suffix=SUFFIX append an additional SUFFIX to file names
-b, --bytes=SIZE put SIZE bytes per output file
-C, --line-bytes=SIZE put at most SIZE bytes of records per output file
-d use numeric suffixes starting at 0, not alphabetic
--numeric-suffixes[=FROM] same as -d, but allow setting the start value
-x use hex suffixes starting at 0, not alphabetic
--hex-suffixes[=FROM] same as -x, but allow setting the start value
-e, --elide-empty-files do not generate empty output files with '-n'
--filter=COMMAND write to shell COMMAND; file name is $FILE
-l, --lines=NUMBER put NUMBER lines/records per output file
-n, --number=CHUNKS generate CHUNKS output files; see explanation below
-t, --separator=SEP use SEP instead of newline as the record separator;
'\0' (zero) specifies the NUL character
-u, --unbuffered immediately copy input to output with '-n r/...'
--verbose print a diagnostic just before each
output file is opened
--help display this help and exit
--version output version information and exit
The SIZE argument is an integer and optional unit (example: 10K is 10*1024).
Units are K,M,G,T,P,E,Z,Y (powers of 1024) or KB,MB,... (powers of 1000).
Binary prefixes can be used, too: KiB=K, MiB=M, and so on.
CHUNKS may be:
N split into N files based on size of input
K/N output Kth of N to stdout
l/N split into N files without splitting lines/records
l/K/N output Kth of N to stdout without splitting lines/records
r/N like 'l' but use round robin distribution
r/K/N likewise but only output Kth of N to stdout
GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
Full documentation <https://www.gnu.org/software/coreutils/split>
or available locally via: info '(coreutils) split invocation'
stat
Display file or file system status.
user $stat --helpUsage: stat [OPTION]... FILE...
Display file or file system status.
Mandatory arguments to long options are mandatory for short options too.
-L, --dereference follow links
-f, --file-system display file system status instead of file status
--cached=MODE specify how to use cached attributes;
useful on remote file systems. See MODE below
-c --format=FORMAT use the specified FORMAT instead of the default;
output a newline after each use of FORMAT
--printf=FORMAT like --format, but interpret backslash escapes,
and do not output a mandatory trailing newline;
if you want a newline, include \n in FORMAT
-t, --terse print the information in terse form
--help display this help and exit
--version output version information and exit
The --cached MODE argument can be; always, never, or default.
`always` will use cached attributes if available, while
`never` will try to synchronize with the latest attributes, and
`default` will leave it up to the underlying file system.
The valid format sequences for files (without --file-system):
%a permission bits in octal (note '#' and '0' printf flags)
%A permission bits and file type in human readable form
%b number of blocks allocated (see %B)
%B the size in bytes of each block reported by %b
%C SELinux security context string
%d device number in decimal
%D device number in hex
%f raw mode in hex
%F file type
%g group ID of owner
%G group name of owner
%h number of hard links
%i inode number
%m mount point
%n file name
%N quoted file name with dereference if symbolic link
%o optimal I/O transfer size hint
%s total size, in bytes
%t major device type in hex, for character/block device special files
%T minor device type in hex, for character/block device special files
%u user ID of owner
%U user name of owner
%w time of file birth, human-readable; - if unknown
%W time of file birth, seconds since Epoch; 0 if unknown
%x time of last access, human-readable
%X time of last access, seconds since Epoch
%y time of last data modification, human-readable
%Y time of last data modification, seconds since Epoch
%z time of last status change, human-readable
%Z time of last status change, seconds since Epoch
Valid format sequences for file systems:
%a free blocks available to non-superuser
%b total data blocks in file system
%c total file nodes in file system
%d free file nodes in file system
%f free blocks in file system
%i file system ID in hex
%l maximum length of filenames
%n file name
%s block size (for faster transfers)
%S fundamental block size (for block counts)
%t file system type in hex
%T file system type in human readable form
--terse is equivalent to the following FORMAT:
%n %s %b %f %u %g %D %i %h %t %T %X %Y %Z %W %o
--terse --file-system is equivalent to the following FORMAT:
%n %i %l %t %s %S %b %f %a %c %d
NOTE: your shell may have its own version of stat, which usually supersedes
the version described here. Please refer to your shell's documentation
for details about the options it supports.
GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
Full documentation <https://www.gnu.org/software/coreutils/stat>
or available locally via: info '(coreutils) stat invocation'
stdbuf
Run COMMAND, with modified buffering operations for its standard streams.
user $stdbuf --helpUsage: stdbuf OPTION... COMMAND
Run COMMAND, with modified buffering operations for its standard streams.
Mandatory arguments to long options are mandatory for short options too.
-i, --input=MODE adjust standard input stream buffering
-o, --output=MODE adjust standard output stream buffering
-e, --error=MODE adjust standard error stream buffering
--help display this help and exit
--version output version information and exit
If MODE is 'L' the corresponding stream will be line buffered.
This option is invalid with standard input.
If MODE is '0' the corresponding stream will be unbuffered.
Otherwise MODE is a number which may be followed by one of the following:
KB 1000, K 1024, MB 1000*1000, M 1024*1024, and so on for G, T, P, E, Z, Y.
Binary prefixes can be used, too: KiB=K, MiB=M, and so on.
In this case the corresponding stream will be fully buffered with the buffer
size set to MODE bytes.
NOTE: If COMMAND adjusts the buffering of its standard streams ('tee' does
for example) then that will override corresponding changes by 'stdbuf'.
Also some filters (like 'dd' and 'cat' etc.) don't use streams for I/O,
and are thus unaffected by 'stdbuf' settings.
GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
Full documentation <https://www.gnu.org/software/coreutils/stdbuf>
or available locally via: info '(coreutils) stdbuf invocation'
stty
Change and print terminal line settings.
user $stty --helpUsage: stty [-F DEVICE | --file=DEVICE] [SETTING]...
or: stty [-F DEVICE | --file=DEVICE] [-a|--all]
or: stty [-F DEVICE | --file=DEVICE] [-g|--save]
Print or change terminal characteristics.
Mandatory arguments to long options are mandatory for short options too.
-a, --all print all current settings in human-readable form
-g, --save print all current settings in a stty-readable form
-F, --file=DEVICE open and use the specified DEVICE instead of stdin
--help display this help and exit
--version output version information and exit
Optional - before SETTING indicates negation. An * marks non-POSIX
settings. The underlying system defines which settings are available.
Special characters:
* discard CHAR CHAR will toggle discarding of output
eof CHAR CHAR will send an end of file (terminate the input)
eol CHAR CHAR will end the line
* eol2 CHAR alternate CHAR for ending the line
erase CHAR CHAR will erase the last character typed
intr CHAR CHAR will send an interrupt signal
kill CHAR CHAR will erase the current line
* lnext CHAR CHAR will enter the next character quoted
quit CHAR CHAR will send a quit signal
* rprnt CHAR CHAR will redraw the current line
start CHAR CHAR will restart the output after stopping it
stop CHAR CHAR will stop the output
susp CHAR CHAR will send a terminal stop signal
* swtch CHAR CHAR will switch to a different shell layer
* werase CHAR CHAR will erase the last word typed
Special settings:
N set the input and output speeds to N bauds
* cols N tell the kernel that the terminal has N columns
* columns N same as cols N
* [-]drain wait for transmission before applying settings (on by default)
ispeed N set the input speed to N
* line N use line discipline N
min N with -icanon, set N characters minimum for a completed read
ospeed N set the output speed to N
* rows N tell the kernel that the terminal has N rows
* size print the number of rows and columns according to the kernel
speed print the terminal speed
time N with -icanon, set read timeout of N tenths of a second
Control settings:
[-]clocal disable modem control signals
[-]cread allow input to be received
* [-]crtscts enable RTS/CTS handshaking
csN set character size to N bits, N in [5..8]
[-]cstopb use two stop bits per character (one with '-')
[-]hup send a hangup signal when the last process closes the tty
[-]hupcl same as [-]hup
[-]parenb generate parity bit in output and expect parity bit in input
[-]parodd set odd parity (or even parity with '-')
* [-]cmspar use "stick" (mark/space) parity
Input settings:
[-]brkint breaks cause an interrupt signal
[-]icrnl translate carriage return to newline
[-]ignbrk ignore break characters
[-]igncr ignore carriage return
[-]ignpar ignore characters with parity errors
* [-]imaxbel beep and do not flush a full input buffer on a character
[-]inlcr translate newline to carriage return
[-]inpck enable input parity checking
[-]istrip clear high (8th) bit of input characters
* [-]iutf8 assume input characters are UTF-8 encoded
* [-]iuclc translate uppercase characters to lowercase
* [-]ixany let any character restart output, not only start character
[-]ixoff enable sending of start/stop characters
[-]ixon enable XON/XOFF flow control
[-]parmrk mark parity errors (with a 255-0-character sequence)
[-]tandem same as [-]ixoff
Output settings:
* bsN backspace delay style, N in [0..1]
* crN carriage return delay style, N in [0..3]
* ffN form feed delay style, N in [0..1]
* nlN newline delay style, N in [0..1]
* [-]ocrnl translate carriage return to newline
* [-]ofdel use delete characters for fill instead of NUL characters
* [-]ofill use fill (padding) characters instead of timing for delays
* [-]olcuc translate lowercase characters to uppercase
* [-]onlcr translate newline to carriage return-newline
* [-]onlret newline performs a carriage return
* [-]onocr do not print carriage returns in the first column
[-]opost postprocess output
* tabN horizontal tab delay style, N in [0..3]
* tabs same as tab0
* -tabs same as tab3
* vtN vertical tab delay style, N in [0..1]
Local settings:
[-]crterase echo erase characters as backspace-space-backspace
* crtkill kill all line by obeying the echoprt and echoe settings
* -crtkill kill all line by obeying the echoctl and echok settings
* [-]ctlecho echo control characters in hat notation ('^c')
[-]echo echo input characters
* [-]echoctl same as [-]ctlecho
[-]echoe same as [-]crterase
[-]echok echo a newline after a kill character
* [-]echoke same as [-]crtkill
[-]echonl echo newline even if not echoing other characters
* [-]echoprt echo erased characters backward, between '\' and '/'
* [-]extproc enable "LINEMODE"; useful with high latency links
* [-]flusho discard output
[-]icanon enable special characters: erase, kill, werase, rprnt
[-]iexten enable non-POSIX special characters
[-]isig enable interrupt, quit, and suspend special characters
[-]noflsh disable flushing after interrupt and quit special characters
* [-]prterase same as [-]echoprt
* [-]tostop stop background jobs that try to write to the terminal
* [-]xcase with icanon, escape with '\' for uppercase characters
Combination settings:
* [-]LCASE same as [-]lcase
cbreak same as -icanon
-cbreak same as icanon
cooked same as brkint ignpar istrip icrnl ixon opost isig
icanon, eof and eol characters to their default values
-cooked same as raw
crt same as echoe echoctl echoke
dec same as echoe echoctl echoke -ixany intr ^c erase 0177
kill ^u
* [-]decctlq same as [-]ixany
ek erase and kill characters to their default values
evenp same as parenb -parodd cs7
-evenp same as -parenb cs8
* [-]lcase same as xcase iuclc olcuc
litout same as -parenb -istrip -opost cs8
-litout same as parenb istrip opost cs7
nl same as -icrnl -onlcr
-nl same as icrnl -inlcr -igncr onlcr -ocrnl -onlret
oddp same as parenb parodd cs7
-oddp same as -parenb cs8
[-]parity same as [-]evenp
pass8 same as -parenb -istrip cs8
-pass8 same as parenb istrip cs7
raw same as -ignbrk -brkint -ignpar -parmrk -inpck -istrip
-inlcr -igncr -icrnl -ixon -ixoff -icanon -opost
-isig -iuclc -ixany -imaxbel -xcase min 1 time 0
-raw same as cooked
sane same as cread -ignbrk brkint -inlcr -igncr icrnl
icanon iexten echo echoe echok -echonl -noflsh
-ixoff -iutf8 -iuclc -ixany imaxbel -xcase -olcuc -ocrnl
opost -ofill onlcr -onocr -onlret nl0 cr0 tab0 bs0 vt0 ff0
isig -tostop -ofdel -echoprt echoctl echoke -extproc -flusho,
all special characters to their default values
Handle the tty line connected to standard input. Without arguments,
prints baud rate, line discipline, and deviations from stty sane. In
settings, CHAR is taken literally, or coded as in ^c, 0x37, 0177 or
127; special values ^- or undef used to disable special characters.
GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
Full documentation <https://www.gnu.org/software/coreutils/stty>
or available locally via: info '(coreutils) stty invocation'
sum
Checksum and count the blocks in a file.
user $sum --helpUsage: sum [OPTION]... [FILE]...
Print checksum and block counts for each FILE.
With no FILE, or when FILE is -, read standard input.
-r use BSD sum algorithm, use 1K blocks
-s, --sysv use System V sum algorithm, use 512 bytes blocks
--help display this help and exit
--version output version information and exit
GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
Full documentation <https://www.gnu.org/software/coreutils/sum>
or available locally via: info '(coreutils) sum invocation'
sync
Synchronize cached writes to persistent storage.
user $sync --helpUsage: sync [OPTION] [FILE]...
Synchronize cached writes to persistent storage
If one or more files are specified, sync only them,
or their containing file systems.
-d, --data sync only file data, no unneeded metadata
-f, --file-system sync the file systems that contain the files
--help display this help and exit
--version output version information and exit
GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
Full documentation <https://www.gnu.org/software/coreutils/sync>
or available locally via: info '(coreutils) sync invocation'
tac
Concatenate and print files in reverse.
user $tac --helpUsage: tac [OPTION]... [FILE]...
Write each FILE to standard output, last line first.
With no FILE, or when FILE is -, read standard input.
Mandatory arguments to long options are mandatory for short options too.
-b, --before attach the separator before instead of after
-r, --regex interpret the separator as a regular expression
-s, --separator=STRING use STRING as the separator instead of newline
--help display this help and exit
--version output version information and exit
GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
Full documentation <https://www.gnu.org/software/coreutils/tac>
or available locally via: info '(coreutils) tac invocation'
tail
Output the last part of files.
user $tail --helpUsage: tail [OPTION]... [FILE]...
Print the last 10 lines of each FILE to standard output.
With more than one FILE, precede each with a header giving the file name.
With no FILE, or when FILE is -, read standard input.
Mandatory arguments to long options are mandatory for short options too.
-c, --bytes=[+]NUM output the last NUM bytes; or use -c +NUM to
output starting with byte NUM of each file
-f, --follow[={name|descriptor}]
output appended data as the file grows;
an absent option argument means 'descriptor'
-F same as --follow=name --retry
-n, --lines=[+]NUM output the last NUM lines, instead of the last 10;
or use -n +NUM to output starting with line NUM
--max-unchanged-stats=N
with --follow=name, reopen a FILE which has not
changed size after N (default 5) iterations
to see if it has been unlinked or renamed
(this is the usual case of rotated log files);
with inotify, this option is rarely useful
--pid=PID with -f, terminate after process ID, PID dies
-q, --quiet, --silent never output headers giving file names
--retry keep trying to open a file if it is inaccessible
-s, --sleep-interval=N with -f, sleep for approximately N seconds
(default 1.0) between iterations;
with inotify and --pid=P, check process P at
least once every N seconds
-v, --verbose always output headers giving file names
-z, --zero-terminated line delimiter is NUL, not newline
--help display this help and exit
--version output version information and exit
NUM may have a multiplier suffix:
b 512, kB 1000, K 1024, MB 1000*1000, M 1024*1024,
GB 1000*1000*1000, G 1024*1024*1024, and so on for T, P, E, Z, Y.
Binary prefixes can be used, too: KiB=K, MiB=M, and so on.
With --follow (-f), tail defaults to following the file descriptor, which
means that even if a tail'ed file is renamed, tail will continue to track
its end. This default behavior is not desirable when you really want to
track the actual name of the file, not the file descriptor (e.g., log
rotation). Use --follow=name in that case. That causes tail to track the
named file in a way that accommodates renaming, removal and creation.
GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
Full documentation <https://www.gnu.org/software/coreutils/tail>
or available locally via: info '(coreutils) tail invocation'
tee
Read from standard input and write to standard output and files.
user $tee --helpUsage: tee [OPTION]... [FILE]...
Copy standard input to each FILE, and also to standard output.
-a, --append append to the given FILEs, do not overwrite
-i, --ignore-interrupts ignore interrupt signals
-p diagnose errors writing to non pipes
--output-error[=MODE] set behavior on write error. See MODE below
--help display this help and exit
--version output version information and exit
MODE determines behavior with write errors on the outputs:
'warn' diagnose errors writing to any output
'warn-nopipe' diagnose errors writing to any output not a pipe
'exit' exit on error writing to any output
'exit-nopipe' exit on error writing to any output not a pipe
The default MODE for the -p option is 'warn-nopipe'.
The default operation when --output-error is not specified, is to
exit immediately on error writing to a pipe, and diagnose errors
writing to non pipe outputs.
GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
Full documentation <https://www.gnu.org/software/coreutils/tee>
or available locally via: info '(coreutils) tee invocation'
test
Perform tests on files and text.
/usr/bin/test command does not seem to have --help option.
timeout
Run a command with a time limit.
user $timeout --helpUsage: timeout [OPTION] DURATION COMMAND [ARG]...
or: timeout [OPTION]
Start COMMAND, and kill it if still running after DURATION.
Mandatory arguments to long options are mandatory for short options too.
--preserve-status
exit with the same status as COMMAND, even when the
command times out
--foreground
when not running timeout directly from a shell prompt,
allow COMMAND to read from the TTY and get TTY signals;
in this mode, children of COMMAND will not be timed out
-k, --kill-after=DURATION
also send a KILL signal if COMMAND is still running
this long after the initial signal was sent
-s, --signal=SIGNAL
specify the signal to be sent on timeout;
SIGNAL may be a name like 'HUP' or a number;
see 'kill -l' for a list of signals
-v, --verbose diagnose to stderr any signal sent upon timeout
--help display this help and exit
--version output version information and exit
DURATION is a floating point number with an optional suffix:
's' for seconds (the default), 'm' for minutes, 'h' for hours or 'd' for days.
A duration of 0 disables the associated timeout.
If the command times out, and --preserve-status is not set, then exit with
status 124. Otherwise, exit with the status of COMMAND. If no signal
is specified, send the TERM signal upon timeout. The TERM signal kills
any process that does not block or catch that signal. It may be necessary
to use the KILL (9) signal, since this signal cannot be caught, in which
case the exit status is 128+9 rather than 124.
GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
Full documentation <https://www.gnu.org/software/coreutils/timeout>
or available locally via: info '(coreutils) timeout invocation'
touch
Change file timestamps.
user $touch --helpUsage: touch [OPTION]... FILE...
Update the access and modification times of each FILE to the current time.
A FILE argument that does not exist is created empty, unless -c or -h
is supplied.
A FILE argument string of - is handled specially and causes touch to
change the times of the file associated with standard output.
Mandatory arguments to long options are mandatory for short options too.
-a change only the access time
-c, --no-create do not create any files
-d, --date=STRING parse STRING and use it instead of current time
-f (ignored)
-h, --no-dereference affect each symbolic link instead of any referenced
file (useful only on systems that can change the
timestamps of a symlink)
-m change only the modification time
-r, --reference=FILE use this file's times instead of current time
-t STAMP use [[CC]YY]MMDDhhmm[.ss] instead of current time
--time=WORD change the specified time:
WORD is access, atime, or use: equivalent to -a
WORD is modify or mtime: equivalent to -m
--help display this help and exit
--version output version information and exit
Note that the -d and -t options accept different time-date formats.
GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
Full documentation <https://www.gnu.org/software/coreutils/touch>
or available locally via: info '(coreutils) touch invocation'
tr
Translate or delete characters.
user $tr --helpUsage: tr [OPTION]... SET1 [SET2]
Translate, squeeze, and/or delete characters from standard input,
writing to standard output.
-c, -C, --complement use the complement of SET1
-d, --delete delete characters in SET1, do not translate
-s, --squeeze-repeats replace each sequence of a repeated character
that is listed in the last specified SET,
with a single occurrence of that character
-t, --truncate-set1 first truncate SET1 to length of SET2
--help display this help and exit
--version output version information and exit
SETs are specified as strings of characters. Most represent themselves.
Interpreted sequences are:
\NNN character with octal value NNN (1 to 3 octal digits)
\\ backslash
\a audible BEL
\b backspace
\f form feed
\n new line
\r return
\t horizontal tab
\v vertical tab
CHAR1-CHAR2 all characters from CHAR1 to CHAR2 in ascending order
[CHAR*] in SET2, copies of CHAR until length of SET1
[CHAR*REPEAT] REPEAT copies of CHAR, REPEAT octal if starting with 0
[:alnum:] all letters and digits
[:alpha:] all letters
[:blank:] all horizontal whitespace
[:cntrl:] all control characters
[:digit:] all digits
[:graph:] all printable characters, not including space
[:lower:] all lower case letters
[:print:] all printable characters, including space
[:punct:] all punctuation characters
[:space:] all horizontal or vertical whitespace
[:upper:] all upper case letters
[:xdigit:] all hexadecimal digits
[=CHAR=] all characters which are equivalent to CHAR
Translation occurs if -d is not given and both SET1 and SET2 appear.
-t may be used only when translating. SET2 is extended to length of
SET1 by repeating its last character as necessary. Excess characters
of SET2 are ignored. Only [:lower:] and [:upper:] are guaranteed to
expand in ascending order; used in SET2 while translating, they may
only be used in pairs to specify case conversion. -s uses the last
specified SET, and occurs after translation or deletion.
GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
Full documentation <https://www.gnu.org/software/coreutils/tr>
or available locally via: info '(coreutils) tr invocation'
true
Return a successful result.
user $/bin/true --helpUsage: /bin/true [ignored command line arguments]
or: /bin/true OPTION
Exit with a status code indicating success.
--help display this help and exit
--version output version information and exit
NOTE: your shell may have its own version of true, which usually supersedes
the version described here. Please refer to your shell's documentation
for details about the options it supports.
GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
Full documentation <https://www.gnu.org/software/coreutils/true>
or available locally via: info '(coreutils) true invocation'
n.b. Some shells have a true command built in, which is why this needs the /bin prefix to return the help text.
truncate
Shrink or extend the size of a file to the specified size.
user $truncate --helpUsage: truncate OPTION... FILE...
Shrink or extend the size of each FILE to the specified size
A FILE argument that does not exist is created.
If a FILE is larger than the specified size, the extra data is lost.
If a FILE is shorter, it is extended and the sparse extended part (hole)
reads as zero bytes.
Mandatory arguments to long options are mandatory for short options too.
-c, --no-create do not create any files
-o, --io-blocks treat SIZE as number of IO blocks instead of bytes
-r, --reference=RFILE base size on RFILE
-s, --size=SIZE set or adjust the file size by SIZE bytes
--help display this help and exit
--version output version information and exit
The SIZE argument is an integer and optional unit (example: 10K is 10*1024).
Units are K,M,G,T,P,E,Z,Y (powers of 1024) or KB,MB,... (powers of 1000).
Binary prefixes can be used, too: KiB=K, MiB=M, and so on.
SIZE may also be prefixed by one of the following modifying characters:
'+' extend by, '-' reduce by, '<' at most, '>' at least,
'/' round down to multiple of, '%' round up to multiple of.
GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
Full documentation <https://www.gnu.org/software/coreutils/truncate>
or available locally via: info '(coreutils) truncate invocation'
tsort
Perform topological sort.
user $tsort --helpUsage: tsort [OPTION] [FILE]
Write totally ordered list consistent with the partial ordering in FILE.
With no FILE, or when FILE is -, read standard input.
--help display this help and exit
--version output version information and exit
GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
Full documentation <https://www.gnu.org/software/coreutils/tsort>
or available locally via: info '(coreutils) tsort invocation'
tty
Print the file name of the terminal connected to standard input.
user $tty --helpUsage: tty [OPTION]...
Print the file name of the terminal connected to standard input.
-s, --silent, --quiet print nothing, only return an exit status
--help display this help and exit
--version output version information and exit
GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
Full documentation <https://www.gnu.org/software/coreutils/tty>
or available locally via: info '(coreutils) tty invocation'
uname
Print system information.
user $uname --helpUsage: uname [OPTION]...
Print certain system information. With no OPTION, same as -s.
-a, --all print all information, in the following order,
except omit -p and -i if unknown:
-s, --kernel-name print the kernel name
-n, --nodename print the network node hostname
-r, --kernel-release print the kernel release
-v, --kernel-version print the kernel version
-m, --machine print the machine hardware name
-p, --processor print the processor type (non-portable)
-i, --hardware-platform print the hardware platform (non-portable)
-o, --operating-system print the operating system
--help display this help and exit
--version output version information and exit
GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
Full documentation <https://www.gnu.org/software/coreutils/uname>
or available locally via: info '(coreutils) uname invocation'
unexpand
Convert spaces to tabs.
user $unexpand --helpUsage: unexpand [OPTION]... [FILE]...
Convert blanks in each FILE to tabs, writing to standard output.
With no FILE, or when FILE is -, read standard input.
Mandatory arguments to long options are mandatory for short options too.
-a, --all convert all blanks, instead of just initial blanks
--first-only convert only leading sequences of blanks (overrides -a)
-t, --tabs=N have tabs N characters apart instead of 8 (enables -a)
-t, --tabs=LIST use comma separated list of tab positions
The last specified position can be prefixed with '/'
to specify a tab size to use after the last
explicitly specified tab stop. Also a prefix of '+'
can be used to align remaining tab stops relative to
the last specified tab stop instead of the first column
--help display this help and exit
--version output version information and exit
GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
Full documentation <https://www.gnu.org/software/coreutils/unexpand>
or available locally via: info '(coreutils) unexpand invocation'
uniq
Report or omit repeated lines.
user $uniq --helpUsage: uniq [OPTION]... [INPUT [OUTPUT]]
Filter adjacent matching lines from INPUT (or standard input),
writing to OUTPUT (or standard output).
With no options, matching lines are merged to the first occurrence.
Mandatory arguments to long options are mandatory for short options too.
-c, --count prefix lines by the number of occurrences
-d, --repeated only print duplicate lines, one for each group
-D print all duplicate lines
--all-repeated[=METHOD] like -D, but allow separating groups
with an empty line;
METHOD={none(default),prepend,separate}
-f, --skip-fields=N avoid comparing the first N fields
--group[=METHOD] show all items, separating groups with an empty line;
METHOD={separate(default),prepend,append,both}
-i, --ignore-case ignore differences in case when comparing
-s, --skip-chars=N avoid comparing the first N characters
-u, --unique only print unique lines
-z, --zero-terminated line delimiter is NUL, not newline
-w, --check-chars=N compare no more than N characters in lines
--help display this help and exit
--version output version information and exit
A field is a run of blanks (usually spaces and/or TABs), then non-blank
characters. Fields are skipped before chars.
Note: 'uniq' does not detect repeated lines unless they are adjacent.
You may want to sort the input first, or use 'sort -u' without 'uniq'.
GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
Full documentation <https://www.gnu.org/software/coreutils/uniq>
or available locally via: info '(coreutils) uniq invocation'
unlink
Call the unlink function to remove the specified file.
user $unlink --helpUsage: unlink FILE
or: unlink OPTION
Call the unlink function to remove the specified FILE.
--help display this help and exit
--version output version information and exit
GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
Full documentation <https://www.gnu.org/software/coreutils/unlink>
or available locally via: info '(coreutils) unlink invocation'
users
Print the user names of users currently logged in to the current host.
user $users --helpUsage: users [OPTION]... [FILE]
Output who is currently logged in according to FILE.
If FILE is not specified, use /var/run/utmp. /var/log/wtmp as FILE is common.
--help display this help and exit
--version output version information and exit
GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
Full documentation <https://www.gnu.org/software/coreutils/users>
or available locally via: info '(coreutils) users invocation'
vdir
List directory contents.
user $vdir --helpUsage: vdir [OPTION]... [FILE]...
List information about the FILEs (the current directory by default).
Sort entries alphabetically if none of -cftuvSUX nor --sort is specified.
Mandatory arguments to long options are mandatory for short options too.
-a, --all do not ignore entries starting with .
-A, --almost-all do not list implied . and ..
--author with -l, print the author of each file
-b, --escape print C-style escapes for nongraphic characters
--block-size=SIZE with -l, scale sizes by SIZE when printing them;
e.g., '--block-size=M'; see SIZE format below
-B, --ignore-backups do not list implied entries ending with ~
-c with -lt: sort by, and show, ctime (time of last
modification of file status information);
with -l: show ctime and sort by name;
otherwise: sort by ctime, newest first
-C list entries by columns
--color[=WHEN] colorize the output; WHEN can be 'always' (default
if omitted), 'auto', or 'never'; more info below
-d, --directory list directories themselves, not their contents
-D, --dired generate output designed for Emacs' dired mode
-f do not sort, enable -aU, disable -ls --color
-F, --classify append indicator (one of */=>@|) to entries
--file-type likewise, except do not append '*'
--format=WORD across -x, commas -m, horizontal -x, long -l,
single-column -1, verbose -l, vertical -C
--full-time like -l --time-style=full-iso
-g like -l, but do not list owner
--group-directories-first
group directories before files;
can be augmented with a --sort option, but any
use of --sort=none (-U) disables grouping
-G, --no-group in a long listing, don't print group names
-h, --human-readable with -l and -s, print sizes like 1K 234M 2G etc.
--si likewise, but use powers of 1000 not 1024
-H, --dereference-command-line
follow symbolic links listed on the command line
--dereference-command-line-symlink-to-dir
follow each command line symbolic link
that points to a directory
--hide=PATTERN do not list implied entries matching shell PATTERN
(overridden by -a or -A)
--hyperlink[=WHEN] hyperlink file names; WHEN can be 'always'
(default if omitted), 'auto', or 'never'
--indicator-style=WORD append indicator with style WORD to entry names:
none (default), slash (-p),
file-type (--file-type), classify (-F)
-i, --inode print the index number of each file
-I, --ignore=PATTERN do not list implied entries matching shell PATTERN
-k, --kibibytes default to 1024-byte blocks for disk usage;
used only with -s and per directory totals
-l use a long listing format
-L, --dereference when showing file information for a symbolic
link, show information for the file the link
references rather than for the link itself
-m fill width with a comma separated list of entries
-n, --numeric-uid-gid like -l, but list numeric user and group IDs
-N, --literal print entry names without quoting
-o like -l, but do not list group information
-p, --indicator-style=slash
append / indicator to directories
-q, --hide-control-chars print ? instead of nongraphic characters
--show-control-chars show nongraphic characters as-is (the default,
unless program is 'ls' and output is a terminal)
-Q, --quote-name enclose entry names in double quotes
--quoting-style=WORD use quoting style WORD for entry names:
literal, locale, shell, shell-always,
shell-escape, shell-escape-always, c, escape
(overrides QUOTING_STYLE environment variable)
-r, --reverse reverse order while sorting
-R, --recursive list subdirectories recursively
-s, --size print the allocated size of each file, in blocks
-S sort by file size, largest first
--sort=WORD sort by WORD instead of name: none (-U), size (-S),
time (-t), version (-v), extension (-X)
--time=WORD change the default of using modification times;
access time (-u): atime, access, use;
change time (-c): ctime, status;
birth time: birth, creation;
with -l, WORD determines which time to show;
with --sort=time, sort by WORD (newest first)
--time-style=TIME_STYLE time/date format with -l; see TIME_STYLE below
-t sort by time, newest first; see --time
-T, --tabsize=COLS assume tab stops at each COLS instead of 8
-u with -lt: sort by, and show, access time;
with -l: show access time and sort by name;
otherwise: sort by access time, newest first
-U do not sort; list entries in directory order
-v natural sort of (version) numbers within text
-w, --width=COLS set output width to COLS. 0 means no limit
-x list entries by lines instead of by columns
-X sort alphabetically by entry extension
-Z, --context print any security context of each file
-1 list one file per line. Avoid '\n' with -q or -b
--help display this help and exit
--version output version information and exit
The SIZE argument is an integer and optional unit (example: 10K is 10*1024).
Units are K,M,G,T,P,E,Z,Y (powers of 1024) or KB,MB,... (powers of 1000).
Binary prefixes can be used, too: KiB=K, MiB=M, and so on.
The TIME_STYLE argument can be full-iso, long-iso, iso, locale, or +FORMAT.
FORMAT is interpreted like in date(1). If FORMAT is FORMAT1<newline>FORMAT2,
then FORMAT1 applies to non-recent files and FORMAT2 to recent files.
TIME_STYLE prefixed with 'posix-' takes effect only outside the POSIX locale.
Also the TIME_STYLE environment variable sets the default style to use.
Using color to distinguish file types is disabled both by default and
with --color=never. With --color=auto, ls emits color codes only when
standard output is connected to a terminal. The LS_COLORS environment
variable can change the settings. Use the dircolors command to set it.
Exit status:
0 if OK,
1 if minor problems (e.g., cannot access subdirectory),
2 if serious trouble (e.g., cannot access command-line argument).
GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
Full documentation <https://www.gnu.org/software/coreutils/vdir>
or available locally via: info '(coreutils) vdir invocation'
wc
Print newline, word, and byte counts for each file.
user $wc --helpUsage: wc [OPTION]... [FILE]...
or: wc [OPTION]... --files0-from=F
Print newline, word, and byte counts for each FILE, and a total line if
more than one FILE is specified. A word is a non-zero-length sequence of
characters delimited by white space.
With no FILE, or when FILE is -, read standard input.
The options below may be used to select which counts are printed, always in
the following order: newline, word, character, byte, maximum line length.
-c, --bytes print the byte counts
-m, --chars print the character counts
-l, --lines print the newline counts
--files0-from=F read input from the files specified by
NUL-terminated names in file F;
If F is - then read names from standard input
-L, --max-line-length print the maximum display width
-w, --words print the word counts
--help display this help and exit
--version output version information and exit
GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
Full documentation <https://www.gnu.org/software/coreutils/wc>
or available locally via: info '(coreutils) wc invocation'
who
Show who is logged on.
user $who --helpUsage: who [OPTION]... [ FILE | ARG1 ARG2 ]
Print information about users who are currently logged in.
-a, --all same as -b -d --login -p -r -t -T -u
-b, --boot time of last system boot
-d, --dead print dead processes
-H, --heading print line of column headings
-l, --login print system login processes
--lookup attempt to canonicalize hostnames via DNS
-m only hostname and user associated with stdin
-p, --process print active processes spawned by init
-q, --count all login names and number of users logged on
-r, --runlevel print current runlevel
-s, --short print only name, line, and time (default)
-t, --time print last system clock change
-T, -w, --mesg add user's message status as +, - or ?
-u, --users list users logged in
--message same as -T
--writable same as -T
--help display this help and exit
--version output version information and exit
If FILE is not specified, use /var/run/utmp. /var/log/wtmp as FILE is common.
If ARG1 ARG2 given, -m presumed: 'am i' or 'mom likes' are usual.
GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
Full documentation <https://www.gnu.org/software/coreutils/who>
or available locally via: info '(coreutils) who invocation'
whoami
Print effective userid.
user $whoami --helpUsage: whoami [OPTION]...
Print the user name associated with the current effective user ID.
Same as id -un.
--help display this help and exit
--version output version information and exit
GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
Full documentation <https://www.gnu.org/software/coreutils/whoami>
or available locally via: info '(coreutils) whoami invocation'
yes
Output a string repeatedly until killed.
user $yes --helpUsage: yes [STRING]...
or: yes OPTION
Repeatedly output a line with all specified STRING(s), or 'y'.
--help display this help and exit
--version output version information and exit
GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
Full documentation <https://www.gnu.org/software/coreutils/yes>
or available locally via: info '(coreutils) yes invocation'
See also
- util-linux — contains userspace utilities for Linux-specific system management, including device control, terminal logins, process management, and tty messaging.