how to unrar the rar file in linux

rar is a popular file compress tool in windows, so how we unrar the rarfile under linux.
firstly download the rar software in the url below:
http://www.rarsoft.com/download.htm

secondly use command 'tar -xf RAR 4.01 for Linux' to untar the rar

thirdly cd to rar directory and type 'sudo make' to run the script
after five lines below show in the command line, you've successfully install the rar software.

lastly use 'rar e  filename.rar' to unrar the compressed file