Master Linux Storage: Mount, Unmount, and Auto‑Mount Commands Explained

1. Storage Device Mounting and Unmounting

Common commands: fdisk -l, df, du, mount, umount.

fdisk -l

Purpose: list partition information of all disks, including unmounted partitions and USB devices, to identify device names before mounting.

df

Purpose: display disk space usage of file systems; default unit is KB.

Syntax: df [option] Key options:

-a or --all: show all file systems

-h or --human-readable: display sizes in readable units

-T or --print-type: show file system type

Example:

# df -a

du

Purpose: show disk usage of files or directories. Without arguments, it reports the size of the current directory and its subdirectories.

Syntax: du [option] <path> -a or --all: display size of each file

-h or --human-readable: show sizes in K, M, G

-S or --separate-dirs: show only the total for each argument (uppercase S)

Examples:

# du -h -S ahao

# du -h haha1 haha2

mount

Purpose: without arguments, lists mounted file systems; with arguments, attaches a storage device to a directory.

Syntax: mount [option] <device> <mountpoint> -t<type>: specify file system type (e.g., vfat, iso9660, auto)

Examples:

# mount -t auto /dev/sda5 /ahao

# mount -t auto /dev/sdb1 /ahao

# mount -t iso9660 xxx.iso /peter -o loop

umount

Purpose: detach a mounted file system; using the mount point is recommended.

Syntax: umount <mountpoint> or umount <device> Example:

# umount /ahao

2. Automatic Mounting

Auto‑mount at boot is configured via /etc/fstab. Edit the file with vi or a graphical editor.

/etc/fstab fields

1st: device name, label, or UUID

2nd: mount point

3rd: file system type

4th: mount options (usually defaults)

5th: dump flag (0 or 1)

6th: fsck order (0 or 1)

Example entry to auto‑mount a USB drive without dump or fsck: /dev/sdb1 /usb auto defaults 0 0 Verify the configuration with mount -a.

3. Disk Partitioning

Use fdisk with options d, l, m, n, p, q, t, w, etc., for interactive partitioning.

fdisk command

Purpose: interactive partitioning of disks.

Typical workflow:

Run fdisk /dev/sdb to select the target disk.

Use options such as p to view the partition table, d to delete partitions, n to create new ones, t to change partition type, and w to write changes.

Key options:

m: help

p: print partition table

n: new partition

l: list known partition types

d: delete partition

t: change partition type

w: write and exit

q: quit without saving

During creation, choose partition type (p for primary, e for extended, or l for logical), assign a number (1‑4 for primary/extended, 5+ for logical), set start and end sectors, then verify with p and write with w.

4. Disk Formatting

After partitioning, format partitions with mkfs to create a file system.

mkfs command

Purpose: create a file system on a partition.

Syntax examples:

mkfs -t vfat /dev/sdb1

mkfs.vfat -v /dev/sdb1

Important options:

-t<type>: file system type (e.g., ext4, vfat)

-V: verbose output (must appear before -t)

Example to format with verbose output:

# mkfs -V -t vfat /dev/sdb1