In computing, RAR is a proprietary file format for data compression and archiving, developed by Eugene Roshal (hence the name RAR: Roshal ARchive).
The filename extension used by RAR is .rar . If a RAR-archive is broken into many smaller files (a "multi-volume archive"), as is often the case when it was distributed on Usenet, then those smaller files carry the extensions .rar , .r00 , .r01 , .r02 etc. and most unrar programs reconstruct the whole archive when provided with the .rar file.