7-Zip's RAR (uncompress only) is licensed from WinRAR, so you still have to download the proprietary RAR in these ways: 1. The 'unrar' for Linux 2. WinRAR 3. 7-Zip's RAR implementation is licensed from WinRAR, so they cannot give out source to RAR. (p7zip, for example, does not have RAR support at all) 4. Any other program with RAR licensed from WinRAR.