some quick notes:
ls -l ---- This Will List All Files/Directories In Your Current Directory
ls -al ---- Lists All Files & Information
-l will not list all files, -l is just for (l)ong info line
the -a is for (a)ll, and lists hidden directories and files, (names preceded with a . )
ps -x - show your background processes.
du -sh <dir> shows a human readable summary for the size of a directory.
<cmd> | grep <string> - this will parse all of the output from <cmd> and show only the lines that contain <string>, very useful for machines with lots of processes when you only want to find one. ie: ps -ax | grep named ... this would show the process entry for the dns server.
You have permissions listed but, not the copmmand to change them: chmod <perms> file
Also useful is chown user:group file to change the ownership of a file.
Just a couple of things I think are important, also dont forget that godsend command, "man"