Most Linux distributions automatically detect thumb drive or any usb drive when you plugged it in the computer's usb port. It's the same for cd or dvd. You can check with 'cat /proc/scsi/scsi ' to see if thumb drive is detected.
To see what the thumb drive mount point is, issue this command:
dmesg | grep sd
For cd or dvd drive, replace 'sd' with 'hd' or 'cdrom'.
To mount a thumb drive:
mount -t vfat /dev/sdb1 /mnt/memory
Replace 'sdb1' with your usb or cdrom drive mount point and '/mnt/memory' to where ever you want to mount the drive.
If you are using Ubuntu desktop, no permission needed. That means you can use the device right away after it's been plugged in (of course after it's been detected) .