Hint and kinks

trouble unmounting a USB disk

Sometimes a user has cd'ed to a USB disk in some window (shell) and then if someone else tries to unmount the disk they will get a message like this:

 umount: /media/120514a: umount failed: Operation not permitted

The solution is to find the offending process and kill it cold. If the disk is labeled '120514a', then the steps are:

  lsof | grep 120514a

you might see something like this

 bash       8367       dgs  cwd       DIR       8,49    20480   61341743 /media/120514a/user/cs

you can now kill this offending process as

  kill -9 8367

and then you can do

  umount /media/120514a