Umount all attached usb disks with a single command

Question

Is there a (safe) way to umount all partitions on all attached usb devices (usb-hdds, usb-sticks) with a single commandline command, including several encrypted luks partitions?

Only the partitions on the usb-devices should be umounted, nothing more!

Answer 1

Tried my best to stay posix with this, note that it will fail if you do not have a suitable "udevadm" package available for displaying udev info.

#!/bin/bash

command_exists () {
    type "$1" &> /dev/null
}

CMD=""

if command_exists udevadm; then
        CMD="$(which udevadm) info -q all -n"
fi

if command_exists udevinfo; then
        CMD="$(which udevinfo) -q all -n"
fi

echo "The udevinfo command for this system is $CMD"


for disk in /dev/sd*
do
        DISK=$($CMD $disk | grep ID_BUS)
        if [[ "$DISK" == *usb ]]; then
                echo "$disk is USB, now unmounting.."
                umount $disk
        fi
done