10 Linux shell tricks you don't already know

Venture cake - a new blog on the horizon has written an insightful piece on the different ways in which one can use common commands to achieve complicated tasks in Linux.The blog author provides examples in achieving the following :
A simple way to send output and errors to the same file. It is known as input-output redirection which I had covered a long time back.
Parallelize your loops by backgrounding them.
Catch memory leaks by using top command via cron.
Redirect output from other programs as standard input to a command directly from the command line.
Set a random initial password and force the user to change it.
Add Your Public Key to Remote Machines the Easy Way
Extract an RPM without any additional software
See How a File Has Changed from Factory Defaults
Undo Your Network Screwups After You’ve Lost the Connection
Check which Ports are Open on a remote machine using 'nc' command.
The Easy Way to Extract Tar Archives
Use Bash Shell variables - not the same as Bash shell shortcuts - I may add.
Never reboot a system for NFS failures
Apart from listing examples of each of them, he also provides in a couple of sentences the benefits and drawbacks of each trick. Check out this very interesting article to find out about the examples and explanation provided.