How to manage external drives in Linux - Mount, unmount and format

External drives like USB sticks, SD cards, or SSDs don’t automatically become accessible after connecting them to a Linux system. Before you can use them, you need to mount the device linking its filesystem to your directory tree.

This guide explains how to mount, unmount, and format storage devices safely, along with useful troubleshooting tips.

Table of Contents

• Table of Contents
• Mount a memory drive
  • Step 1: Detect the drive
  • Step 2: Create mount point
  • Step 3: Mount the drive
  • Step 4: Access drive data
  • [Extra] Make the mount permanent
  • Troubleshooting
    • NTFS Filesystem Unsupported
• Unmount a memory drive
• Eject a memory drive
• Format a memory drive

Mount a memory drive

When you plug an external device into your Linux system, it creates a new block device file in the /dev/ directory. However, you can’t use it. First, you need to mount it.

Step 1: Detect the drive

To see the device name, run:

lsblk

Output:

NAME        MAJ:MIN RM  SIZE RO TYPE MOUNTPOINTS
sda           8:0    1  7.4G  0 disk
└─sda1        8:1    1  7.4G  0 part
mmcblk0     179:0    0 58.2G  0 disk
├─mmcblk0p1 179:1    0  512M  0 part /boot/firmware
└─mmcblk0p2 179:2    0 57.7G  0 part /

In this case I plugged a 8 GB USB and Linux named sda. Also you can see that MOUNTPOINTS parameter is empty because the device isn’t mounted.

If you want to get detailed partition information, you can use sudo fdisk -l.

Step 2: Create mount point

On Linux systems by convention there are two places to mount external devices /mnt and /media. The modern behavior is to use on this way:

• /media: Removable drives are usually mounted automatically when plugged in, handled by systemd, udisks or similar.
• /mnt: Remains for manual mounts, often empty by default unless explicitly used.

So I am going to create a folder for mount on /mnt:

sudo mkdir /mnt/usb-sda1

Step 3: Mount the drive

Now you can mount the device partition on previously created mount point:

sudo mount /dev/sda1 /mnt/usb-sda1

To test if the USB if mounted corrected, run:

mount | grep sda1

Output:

/dev/sda1 on /mnt/usb-sda1 type vfat (rw,relatime,fmask=0022,dmask=0022,codepage=437,iocharset=ascii,shortname=mixed,errors=remount-ro)

You can use other commands df -h or lsblk and check Mounted on or MOUNTPOINTS respectively.

Step 4: Access drive data

Finally, you have access to the device and start using it.

cd /mnt/usb-sda1

[Extra] Make the mount permanent

To maintain the device mounted after system reboot you need to edit /etc/fstab file adding this line:

# Generic command:
<device partition or UUID>  <mount point> <filesystem type> <mount options> <dump utility flag> <fsck order at boot>

# For this example case:
/dev/sda1           /mnt/usb-sda1   vfat         defaults    0    0

Use the USB’s UUID in /etc/fstab instead of raw device partition name, which can change if multiple USB drives are connected.

To use device UUID make the following:

 ls -l /dev/disk/by-uuid/*

Output:

lrwxrwxrwx 1 root root 10 Sep 22 09:46 /dev/disk/by-uuid/647A-2882 -> ../../sda1
lrwxrwxrwx 1 root root 15 Sep 22 09:17 /dev/disk/by-uuid/d4cc7d63-da78-48ad-9bdd-64ffbba449a8 -> ../../mmcblk0p2
lrwxrwxrwx 1 root root 15 Sep 22 09:17 /dev/disk/by-uuid/EC36-4DE1 -> ../../mmcblk0p1

Now change the /etc/fstab file’s line with:

/dev/disk/by-uuid/647A-2882           /mnt/usb-sda1   vfat         defaults    0    0

Troubleshooting

NTFS Filesystem Unsupported

Normally, NTFS filesystem isn’t supported by default, so if to attempt to mount a device with that format you will see this error:

mount: /mnt/usb-sdx: no medium found on /dev/sdx.

The solution is to install ntfs-3g package, which adds NTFS read/write support for Linux systems.

Unmount a memory drive

To unmount a device execute the following:

umount /mnt/usb-sda1

To unmount a device, you need to be sure that no process is using it. Otherwise you will see an error like this: umount: /mnt/usb-sda1: target is busy.

Eject a memory drive

sudo eject /dev/sda

Format a memory drive

To format a external device it must be unmounted. On Linux exits the mkfs utility to format devices. To know how many format options you have use the autocomplete:

user@hostname:~ $ mkfs
mkfs         mkfs.cramfs  mkfs.ext2    mkfs.ext4    mkfs.minix   mkfs.ntfs
mkfs.bfs     mkfs.exfat   mkfs.ext3    mkfs.fat     mkfs.msdos   mkfs.vfat

Example command:

sudo mkfs.exfat /dev/sda1

Output:

exfatprogs version : 1.2.0
Creating exFAT filesystem(/dev/sda1, cluster size=32768)

Writing volume boot record: done
Writing backup volume boot record: done
Fat table creation: done
Allocation bitmap creation: done
Upcase table creation: done
Writing root directory entry: done
Synchronizing...

exFAT format complete!