Master Linux Storage: Mount, Unmount, Auto‑Mount, Partition & Format Commands

1. Mounting and Unmounting Storage Devices

Common commands for storage device management are fdisk -l, df, du, mount and umount.

fdisk -l

Purpose: List partition information for all disks, including unmounted partitions and USB devices. Useful for identifying device names before mounting.

Note: Since hardware appears as files in Linux, you can also use ls -l /dev/sda* to view the first disk's partitions.

df

Purpose: Show disk space usage and file‑system statistics, defaulting to kilobytes.

Syntax: df [option] Key options:

-a or --all: display all file systems

-h or --human‑readable: show sizes in a readable format

-T or --print‑type: display the file‑system type

Example:

#df -a

du

Purpose: Report disk usage of files or directories. Without arguments it shows the size of the current directory and its subdirectories; multiple paths can be listed separated by spaces.

Syntax: du [option] <em>path</em> Key options:

-a or --all: display size of each file

-h or --human‑readable: use K, M, G units

-S or --separate‑dirs: show only the total for each specified directory (uppercase S)

Examples:

#du -h -S ahao

#du -h haha1 haha2

mount

Purpose: Without arguments, list all mounted file systems; with arguments, attach a storage device to a directory, making the directory act as the device's access point.

Note: Files that existed in a mount point become hidden after mounting.

Syntax: mount [option] <em>device</em> <em>mount_point</em> Key option: -t<fs_type> (e.g., vfat for FAT32, iso9660 for CD images, auto for automatic detection).

Examples:

#mount -t auto /dev/sda5 /ahao

#mount -t auto /dev/sdb1 /ahao

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

umount

Purpose: Unmount a mounted file system. It is recommended to use the mount point for clarity, especially when a device has multiple mount points.

Syntax: umount <em>mount_point</em> (recommended) umount <em>device</em> Example:

#umount /ahao

2. Automatic Mounting

Automatic mounting at boot is configured via the /etc/fstab file, which can be edited with vi or a graphical editor such as gedit.

/etc/fstab fields

1st column: device name (e.g., /dev/sda1), label, or UUID

2nd column: mount point

3rd column: file‑system type

4th column: mount options (usually defaults)

5th column: dump flag (1 = dump, 0 = no dump)

6th column: fsck order (1 = check, 0 = skip)

Example entry for auto‑mounting a USB drive to /usb without backup or fsck:

/dev/sdb1 /usb auto defaults 0 0

After editing, run mount -a to verify the configuration.

3. Disk Partitioning

When using fdisk in Linux, common options include d, l, m, n, p, q, t, w, etc.

Notes:

Primary and extended partitions are numbered 1‑4; logical partitions start at 5.

If an extended partition exists, only logical partitions can be added.

fdisk command

Purpose: Interactively create, delete, and modify disk partitions.

Usage: fdisk <em>device</em> then enter options such as: m: list help p: display current partition table n: create a new partition l: list known partition types d: delete a partition t: change partition type w: write changes and exit q: quit without saving

Typical workflow:

Use p to view the current table.

Use d to delete unwanted partitions.

Use n to add new partitions, choosing type (p for primary, e for extended, l for logical), number, start and end sectors.

Verify with p again.

Save with w or discard with q.

4. Disk Formatting

After partitioning, a file system must be created on each partition using mkfs (or a specific variant such as mkfs.vfat).

mkfs command

Purpose: Format a partition and create a file system.

Syntax:

mkfs [options] <em>device</em>

mkfs.<em>fs_type</em> [-v] <em>device</em>

Key options:

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

-V: display detailed information (must appear before -t)

Example:

#mkfs -V -t vfat /dev/sdb1

#mkfs.vfat -v /dev/sdb1