on linux, how do I list only mounted removable media / device?

Question

I know we can list all mounted devices using the mount command. or even the df command.

But how can we know if the listed device is removable or not, such as USB, CMROM, External Hardisk, etc?

For this question, we can start with how to do it on SUSE or RedHat.

Thanks!

Answer 1

After thinking about this a bit more, the way to determine if a drive is removable is to check whether the contents of:

/sys/block/sdX/removable

Is set to 0 - non-removable or 1 - removable. You can get the list of mounted drives (presuming the form /dev/sdX where X is a, b, c, etc..) and then loop over the devices checking the contents of the removable file.

For bash using Process-Substitution to feed a while loop to loop over the device names removing the trailing partition digits and only taking unique devices you could do:

#!/bin/bash

while read -r name; do
  if [ "$(<${name/dev/sys\/block}/removable)" -eq "1" ]; then 
    echo "$name - removable"
  else
    echo "$name - non-removable"
  fi
done < <(awk '/^\/dev\/sd/ {sub(/[0-9]+$/,"",$1); print $1}' /proc/mounts | uniq)

Which will list all devices and whether they are removable. For example, running the script with a flash drive inserted (/dev/sdc) and my normal hard drive (/dev/sdb), you would receive:

$ bash list-removable.sh
/dev/sdb - non-removable
/dev/sdc - removable

There are probably many other ways to do it.

Answer 2

You can do something like this:

for dev in /dev/disk/by-id/usb*; do mount | grep $(readlink -f ${dev}); done

This first runs mount to list devices that are mounted. It then looks at /dev/disk/by-id/ which will have a udev link to the device, using the manufacture id of the device. This link will resolve to the /dev/device that it corresponds to. It greps the output of mount for these devices and will display them on the screen along with their current mount points and fs options.

*Edit to include checking against mount