FreeBASIC is a multiplatform, free/open source (GPL) BASIC compiler for Microsoft Windows, protected-mode DOS (DOS extender), Linux, FreeBSD and Xbox. The Xbox version is no longer maintained.According to its official website, FreeBASIC provides syntax compatibility with programs originally written in QuickBASIC. Unlike QuickBASIC, however, FreeBASIC is a command line only compiler, unless users manually install an external IDE of their choice.