Step # 1: Verify or find out your usb partition name
Type the following command to find out USB pen partition name:
# fdisk -l
Step # 2: Format parition
Once identified the partition name type the following command to format the usb pen in Linux (caution you must select correct usb partition name, otherwise you will loss all the data on hard disk):
# mkfs.ext3 /dev/sda1
To format as VFAT/FAT32 file system type the command:
# mkfs.vfat /dev/sda1