When I just got a RAR file from a friend, and prepared to extract it to see the content in RAR archive, I found it asked for a password to extract. Unrar is compatible mostly for Linux distributions where you can easily install the package from the command terminal using the apt programs. RAR is a free tool that is pre-installed on Windows operating systems but unfortunately doesn’t support Linux platforms.
You can use 7-Zip on any computer, including a computer in a commercial organization. Also there is unRAR license restriction for some parts of the code.
Some parts of the code are under the BSD 3-clause License. The most of the code is under the GNU LGPL license. It uses the official unRAR library internally so it is fully compatible with archives produced by WinRAR.ħ-Zip is free software with open source. Rar Expander is a MacOSX program which extracts the files contained in single or multi-volume RAR archives.