The Archive Browser will decompress RAR files, and most others. To compress, simply select the files and right click and choose "Compress" for a zip file. Creating RAR files is a bit more difficult, as it is a proprietary program. I don't think it is still available, but I licensed it in 2011 from the author, and got both Windows and OS X executables, so I can create RAR files from the command line only on a Mac. I keep the executables backed up and install them on each new version of OS X, and they still work. My version is 4.01.