That website says $400-500

If there is a function or script that prompts you for multiple things you can pipe multiple things that will go through all the prompts. So you could do something like this: "(ls *.zip; yes)| gunzip" to replace existing files. (Same as doing "yes | gunzip *.zip")

Lets say you forgot to put a & at the end of your cmd!! Oh no!!! you can hit Ctrl+Z and enter 'bg' to make that task a background task and get back to a command prompt. nice and renice are excellent for changing processor time priorities (give something more processor time to make it go faster) root and super users can do more with this. On a University or other large scale server you can always type 'last' and see the last machine name and time that everyone logged in from. Grep the output to look for someone in particular. You can use a trace route to track people down this way.