genfstab

Display an fstab compatible output based on a volume label

$ genfstab -L [path/to/mount_point]

$ genfstab -U [path/to/mount_point]

$ genfstab -U [/mnt] >> [/mnt/etc/fstab]

$ genfstab -U [path/to/mount_point] | sudo tee -a /etc/fstab

genfstab [options] [path]

-U
    Use UUIDs for identifying devices. This is the default.

-L
    Use labels for identifying devices.

-t fstypes
    Specify filesystem types to include in the fstab file.
Comma-separated list (e.g., ext4,xfs). Defaults to all filesystem types if not specified.

-p
    Print output to standard output. Otherwise, it will write to /etc/fstab.

-o options
    Append additional options to each fstab entry. Example: -o noatime,discard

-s
    Do not use swap device in output

path
    Optional path to the root filesystem. If specified, genfstab will use this path to determine filesystem information instead of relying on the currently mounted filesystems.

The genfstab command is a utility primarily used in Linux environments, especially during system installation or recovery. Its core function is to automatically generate an /etc/fstab file based on the currently mounted filesystems. The fstab file is crucial for defining how and where filesystems should be mounted during system boot. Instead of manually editing this file (which can be prone to errors), genfstab automatically detects existing partitions, their UUIDs or labels, and their mount points. It then constructs a suitable fstab entry for each. This significantly simplifies the process of configuring persistent filesystem mounting. It can be used with or without root permissions (using the -U or -L flags without root). It relies on querying the kernel and parsing mount information to accurately represent the current filesystem layout in the generated fstab file. It supports multiple output formats to standard output or file as well as filtering mounted file system types.

genfstab relies on the current mount state. If filesystems are not properly mounted, the generated fstab file may be incomplete or incorrect. It's essential to ensure that all intended partitions are mounted before running genfstab. Incorrect entries in /etc/fstab can cause boot failures.

Basic usage: genfstab -p /mnt > fstab
Generates an fstab file based on the mounted filesystems under /mnt and prints the output to fstab file.

Using labels: genfstab -L -p
Generates an fstab file using labels instead of UUIDs and prints the output to standard output.

Specifying filesystem types: genfstab -t ext4,btrfs -p
Only includes ext4 and btrfs filesystem types in the generated fstab file.

genfstab emerged as a convenient tool in Linux distributions, particularly within Arch Linux, to simplify the often-tedious task of creating the /etc/fstab file. Its primary motivation was to automate the process of detecting and representing existing filesystems, UUIDs/labels, and mount points in the correct fstab format. Early versions provided basic functionality. Development has focused on improving accuracy, supporting different filesystem types, and offering options for customization (e.g., UUIDs vs. labels, specific filesystem types). Its adoption has grown alongside the increasing complexity of modern Linux systems and the need for streamlined installation and recovery procedures.

fstab(5), mount(8), blkid(8), findmnt(1)