G

Gigabyte
Abbreviated GB, this is one billion, or 1,073,741,824 bytes.

GREP
(Global Regular Expression and Print). grep, egrep, fgrep - print lines matching a pattern. Grep searches for patterns and displays lines.

Group Permissions
Second set of three bits that define file and directory permissions. Shows the type of access users in the same group as the owner have.

GUI
(Graphic User Interface), refers to an interface and the techniques involved in using a keyboard or a mouse, for instance, to provide an easy-to-use interface to some software.