Filesystem in Userspace

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Filesystem in Userspace (FUSE) provides a way for users to mount file systems without needing special permissions (mounting in Linux is generally reserved to those with administrative privileges).

Installation

Kernel

KERNEL Enable support for FUSE

File systems  --->
    <*> FUSE (Filesystem in Userspace) support

USE flags

USE flags for sys-fs/fuse An interface for filesystems implemented in userspace

`+suid`	Enable setuid root program(s)
`examples`	Install examples, usually source code
`static-libs`	Build static versions of dynamic libraries as well
`test`	Enable dependencies and/or preparations necessary to run tests (usually controlled by FEATURES=test but can be toggled independently)

Data provided by the Gentoo Package Database · Last update: 2025-04-26 12:41 More information about USE flags

Emerge

As with most file systems, after building support for the file system into the kernel be sure to install the user space tools:

root #emerge --ask sys-fs/fuse

Configuration

Files

The following configuration files are available for FUSE:

/etc/fuse.conf

There are two configuration variables available in the fuse.conf file:

mount_max - Sets the maximum number of FUSE mounts allowed to non-root users (defaults to 1000 if unset).
user_allow_other - Allows non-root users to specify the allow_other or allow_root mount options. This is disabled for security reasons.

Usage

Invocation

user $fusermount3 -h

fusermount3: [options] mountpoint
Options:
 -h                 print help
 -V                 print version
 -o opt[,opt...]   mount options
 -u                 unmount
 -q                 quiet
 -z                 lazy unmount

Mounting filesystems

Use the fusermount3 command:

user $fusermount3 /path/to/mountpoint

Unmounting filesystems

Filesystems can be unmounted using either the umount or the fusermount3 command:

user $fusermount3 -u /path/to/mountpoint

Removal

root #emerge --ask --depclean --verbose sys-fs/fuse

Troubleshooting

AppImages

You may see an error message like the one below when executing an AppImage.

user $./app.appimage

AppImages require FUSE to run.
You might still be able to extract the contents of this AppImage
if you run it with the --appimage-extract option.
See https://github.com/AppImage/AppImageKit/wiki/FUSE
for more information

sys-fs/fuse provides fusermount3 but older AppImages may need sys-fs/fuse:0.

root #emerge --ask sys-fs/fuse:0

External resources

Writing a FUSE Filesystem: a Tutorial
FUSE-based file systems (Arch Linux Wiki)