I need to write a simple scripts file that will check if the partition on a USB memory stick has been mounted and then unmount the partition if it is already mounted. Currently, I have an indea to achieve this with the following scripts:

[ -d "/usb/lost+found" ] && umount /usb

I believe this will only work if the partition is formatted with a Un*x/Linux filesystem type. Is there a better way to achieve this regardless what filesystem type?

Try this:

if grep -qE '^[^[:space:]]+ /usb ' /proc/mounts; then
  umount /usb
fi

Thanks for your quick response. FYI, I had to remove the empty space between the "/usb" and "'" to make your scripts to work.

The space was intentional, consider the following example in /proc/mounts:

/dev/sda1 /usb ext3 rw,errors=continue,data=ordered 0 0
/dev/sda2 /usb2 ext3 rw,errors=continue,data=ordered 0 0

Without the additional space, the grep would match the second entry too which could lead to false positives.

Regards,
JoW

You are right. Thanks for this pointer. However, if I include the space, the scripts won't work. For the moment, I have to remove such a space to make it work.