sometimes we need to extract a file. zip or tar.gz files could be opened directly in linux, but rar is not supported. to be able extract a rar file, we should install unrar.
% sudo apt-get install unrar
two useful and most used command is
% unrar e your-file-name.rar #--- to extract the rar file in the current directory
% unrar l your-file-name.rar #-- to list the content of the rar file