General description of this Guide. A complete reference for new Linux users who wish to set up and administer their own Linux home computer, workstation and/or their home or small office network. The answers are meant to be simple, with just sufficient detail, and always supported with a readily usable example. The work is still in progress, but we hope the Guide can be helpful already. We welcome your corrections, advice, criticism, links, translations, and CONTRIBUTIONS. Pls note that there are no ad banners on our pages.

Link: http://linux-newbie.sunsite.dk/

Good idea that.

I think everyone when running linux gradually creates a 'cheatsheet'
of one liners to accomplish tasks they had to work out how to do at first.

Mine is:

lsof -i -P = shows which commands are using which ports
lsof +D /path = shows what files are open (and who has them open) under /path
fuser -n tcp PORTNUM = get the PID using a specific portnumber
du -sh DIR = count the total size of DIR including all subdirs / subfiles
netstat -a -p -l = show all listening processes and their information