GTweak is a command-line script that can be used for tweaking operating systems of Windows family. It has two modes of work: Wizard Mode (for average-skill users) and normal, prompt mode (so called advanced mode). First mentioned mode is the default, user chooses tweaks using keypad. Second is like command prompt, but program supports only its commands. In order to see commands of GTweak, type ? (it shows ReadMe). GTweak comes with a simple script parser (no piping or streaming, just linear parsing), whose usage is described in gtweak.txt file inside the distribution package. Program does not use external utilities, excluding these appended to system. Almost all tweaks are reversible.