Linux Pocket Guide, 2nd Edition

Name

mount — stdin  stdout  - file  -- opt  --help  --version

Synopsis

mount [options] device | directory

The mount command makes a partition accessible. Most commonly it handles disk drives (say, /dev/sda1) and removal media (e.g., USB keys), making them accessible via an existing directory (say, /mnt/mydir):

# mkdir /mnt/mydir
# ls /mnt/mydir                 Notice it’s empty
# mount /dev/sda1 /mnt/mydir
# ls /mnt/mydir
file1      file2      file3     Files on the mounted partition
# df /mnt/mydir
Filesystem     1K-blocks    Used Available Use% Mounted on
/dev/sda1        1011928  285744    674780  30% /mnt/mydir

mount has tons of options and uses; we will discuss only the most basic.

In most common cases, mount reads the file /etc/fstab (filesystem table) to learn how to mount a desired disk. For example, if you type mount /usr, the mount command looks up “/usr” in /etc/fstab, whose line might look like this:

/dev/sda8    /usr    ext3    defaults    1    2

Here mount learns, among other things, that disk device /dev/sda8 should be mounted on /usr as a Linux ext3-formatted filesystem. Now you can mount /dev/sda8 on /usr with either of these commands:

# mount /dev/sda8     by device
# mount /usr          by directory

mount is run typically by the superuser, but common devices like USB and CD-ROM drives often can be mounted and unmounted by any user.

$ mount /media/cdrom

Useful options

-t type	Specify the type of filesystem, such as ext3 or ntfs.
-l	List all mounted filesystems; works with -t too.
-a	Mount all filesystems listed in /etc/fstab. Ignores entries ...