mount Command Cheat Sheet

The mount command serves to attach the filesystem found on some device to the big file tree.

Synopsis

mount -t type device dir

Basic Mounting

Mount a Partition

sudo mount /dev/sdb1 /mnt/data

Mount with Specific Filesystem (-t)

Usually auto-detected, but can be forced.

sudo mount -t ext4 /dev/sdb1 /mnt/data
sudo mount -t vfat /dev/sdc1 /mnt/usb
sudo mount -t ntfs-3g /dev/sdd1 /mnt/windows

View All Mounts

mount

Clean view:

mount | column -t

Or use findmnt.

Advanced Mounting

Bind Mount (--bind)

Remount part of the file hierarchy somewhere else. (e.g., Make /var/www appear in /home/user/www).

sudo mount --bind /var/www /home/user/www

Loop Mount (ISO Files)

Mount a disk image (.iso, .img) as if it were a physical drive.

sudo mount -o loop disk.iso /mnt/iso

Read-Only Mount (-r, -o ro)

sudo mount -o ro /dev/sdb1 /mnt/secure

Remount (rw/ro)

Change permissions without unmounting.

sudo mount -o remount,rw /mnt/secure

The /etc/fstab File

For persistent mounts (survive reboot), edit /etc/fstab.

Syntax: <device> <dir> <type> <options> <dump> <fsck>

Example:

# Device        MountPoint  Type  Options         Dump  Pass
UUID=123-abc    /data       ext4  defaults        0     2
/swapfile       none        swap  sw              0     0
//192.168.1.5/  /mnt/net    cifs  username=guest  0     0

To test fstab without rebooting:

sudo mount -a

Unmounting (umount)

Note: The command is umount, not unmount.

sudo umount /mnt/data

Or by device:

sudo umount /dev/sdb1

"Target is busy"?

If umount fails because the device is busy: 1. Check who is using it: lsof /mnt/data 2. Lazy unmount (detach now, clean up when process finishes):

sudo umount -l /mnt/data

3. Force unmount (Dangerous, data loss risk):

sudo umount -f /mnt/net

(Mostly for network drives).

Notes

Mount Points: The directory /mnt/data must exist before mounting.
UUID: Always prefer UUIDs (blkid) over /dev/sdb1 in fstab, as device names can change.