If you administrating a small or large workstations running with Linux Desktops and want to disable the USB ports for security so that no one can copy the data via pen drive, try the following steps to disable the USB port(s).

Edit the grub.conf and add the following lines(you need to login as root).
# vi /boot/grub/grub.conf

Then add the following lines on the right kernel version

kernel /vmlinuz<your-kernel-version> rhgb quiet nousb

Save and exit the file and reboot the system to disable the USB ports and the boot time.