1. sed useful commands http://www.catonmat.net/blog/wp-content/uploads/2008/09/sed1line.txt
  2. apt and dpkg cheat sheet http://www.cyberciti.biz/tips/linux-debian-package-management-cheat-sheet.html
  3. scripting tutorial http://linuxconfig.org/bash-scripting-tutorial
  4. http://www.cyberciti.biz/faq/linux-unix-bsd-xargs-construct-argument-lists-utility/ has good commands to learn from, on xargs
  5. good hints on writing robust scripts http://www.davidpashley.com/articles/writing-robust-shell-scripts/