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http://www.uic.edu/depts/accc/classes/gnu-linux-101/
Sysadmincasts Video Series
The Linux Filesystem Structure
The Sudoers File
Bash Scripting Tutorial
http://www.catonmat.net/blog/top-ten-one-liners-from-commandlinefu-explained
bash-redirections-cheat-sheet.pdf
Stream Editor (SED) Tutorial