I skip a beat, but any shell user will need this at some point in his life : http://mywiki.wooledge.org/

So many 'I wish I'd known earlier'

Other links straight from #bash@freenode

Topic for #bash is: FAQ: http://mywiki.wooledge.org/BashFAQ | Guide: http://mywiki.wooledge.org/BashGuide | ref: http://xrl.us/bhk9ww | http://wiki.bash-hackers.org/ | USE MORE QUOTES!: http://www.grymoire.com/Unix/Quote.html | Scripts and more: http://www.shelldorado.com/ | New official help mailing list: http://tx0.org/31f

They're all deeply useful