Insert the pendrive in the USB port ,
In command mode su to root mode ,
Check wheather pendrive is mounted or not
From the output of mount get the location where the pendrive is mounted and the block device name .
/de/sdb on /media/USB-STICK type vfat (rw)
USB-STICK -The name of the pendrive
/media/ – Location , where pendrive is mounted
/dev/sdb – The block device name of the pendrive
Now before formatting the pendrive has to be unmounted .
confirm it by giving the mount command again ,wheather mounted or not ,
if not continue ,
Now make the filesystem as u need (fat,ext3 etc)
To format with ext3 filesystem
To format with fat file system
Now mount the pen drive by plugout and plugin or mount by mount command
mount /dev/sdb /LOCATION WHERE TO MOUNT