su
From Gentoo Wiki
The su (substitute user) command can be used to adopt the privileges of other users from the system.
The command is provided by the util-linux package, that has the su USE flag enabled by default. The su command is also available with sys-apps/shadow, that also has a su USE flag. Avoid installing both these commands simultaneously.
Usage
user $su --helpUsage:
su [options] [-] [<user> [<argument>...]]
Change the effective user ID and group ID to that of <user>.
A mere - implies -l. If <user> is not given, root is assumed.
Options:
-m, -p, --preserve-environment do not reset environment variables
-w, --whitelist-environment <list> don't reset specified variables
-g, --group <group> specify the primary group
-G, --supp-group <group> specify a supplemental group
-, -l, --login make the shell a login shell
-c, --command <command> pass a single command to the shell with -c
--session-command <command> pass a single command to the shell with -c
and do not create a new session
-f, --fast pass -f to the shell (for csh or tcsh)
-s, --shell <shell> run <shell> if /etc/shells allows it
-P, --pty create a new pseudo-terminal
-h, --help display this help
-V, --version display version
For more details see su(1).
Adopt root privileges
su will run commands as root by default. Since not specifying a username will cause su to ask for root privileges, the following command will run as root and halt the system:
user $su -c 'shutdown -h now' Tip
It is best practice to encapsulate the commands following the
It is best practice to encapsulate the commands following the
-c option with either single or double quotes.Adopt another user's privileges
It is also possible to specify a user other than root to substitute commands. The following example will run the command echo as the user larry:
user $su -c 'echo "Moo to the Gentoo Wiki reader out there!"' larry