You can't, only your hosting provider has the root server access (and thus the privilege to install or remove packages). Since rar and unrar are CPU intensive scripts I doubt they will though.

@robert - even if his host gives him the ssh access it'll in most cases be limited and he won't be allowed to tamper with system-wide stuff as installing packages.
Mac Reviewed by Mac on . How To Enable and Use Shell Access How To Enable and Use Shell Access ?? Can anyone help me with this plz ?? Rating: 5