user@pcname:~$ fsck
fsck from util-linux 2.27.1
e2fsck 1.42.13 (17-May-2015)
/dev/sda6 is mounted.



WARNING!!!  The filesystem is mounted.   If you continue you ***WILL***
cause ***SEVERE*** filesystem damage.


Do you really want to continue<n>? no
check aborted.
fsck.fat 3.0.28 (2015-05-16)
open: Permission denied