Why knowing a few commands is useful;
     Issuing commands on your own computer;
     Using SSH to log into your Web server;
     Getting your bearings: pwd, cd ls;
     Viewing and moving files: cat, more, head, tail, mv, cp, rm;
     Searching for files: find;
     Looking through and editing files: grep, vi;
     Backing up and restoring files and databases: tar, zip, unzip, mysqldump, mysql;
     File permissions: chmod.  |