# 1. Introduction

This User’s Guide describes several software tools that use the GNAT project facility to drive their behavior. GNAT projects are stored in text files with the extension `.gpr`, commonly called GPR files.

These GPR tools use a common facility, the GNAT Project Manager, that is fully described in GNAT Project Manager.

The main GPR tool is `GPRbuild`, a multi-language builder for systems organized into subsystems and libraries. This tool is described in Building with GPRbuild.

The other GPR tools are described in GPRbuild Companion Tools:

- `GPRconfig`

  A configuration project file generator (see Configuring with GPRconfig).

- `GPRclean`

  A tool to remove compilation artifacts created by GPRbuild (see Cleaning up with GPRclean).

- `GPRinstall`

  Executable and library installer using GPR files (see Installing with GPRinstall).

- `GPRname`

  Naming scheme generator (see Specifying a Naming Scheme with GPRname).

- `GPRls`

  Library browser (see The Library Browser GPRls).