quite easy. You can format your pen drive using two ways:
6. Now unmount the pen drive using the following command
(/dev/sdb1 is the file-system for the USB pen drive)
7. Run the following command to format the USB pen drive
Once the USB drive is formatted, run df command again to see the changes.
Format a USB Pen Drive Using Disks App
Disks is a Linux utility app to manage disk drive, other media and partitions. Disks app can be used to format and partition drives, mount and unmount partitions, edit partitions and create startup disk.
1. Insert your USB pen drive into your Ubuntu PC
2. Open Disks app
3. To open Disks utility app, open Dash and type Disks. Now you can see Disks app icon, click on it to open.
4. You can see the entire disk drive partitions and other media such as pen drive.
5. Select your pen drive from the left column.
6. Click on the settings icon (right side of the box).
see the screenshot below.
7. Select format option.
8. You will be asked for some additional details, select it and click OK.
9. Once everything is done, you can see your pen drive being formatted.
10. That all. Remove your pen drive when its formatted.