ubuntu@ubuntu:~$ sudo e2fsck /dev/sdb1 
e2fsck 1.40.8 (13-Mar-2008)
/dev/sdb1 is mounted.  

WARNING!!!  Running e2fsck on a mounted filesystem may cause
SEVERE filesystem damage.

Do you really want to continue (y/n)? yes

/dev/sdb1: recovering journal
/dev/sdb1: clean, 109856/9396224 files, 901510/37561970 blocks