Useful One Off Recipes
List directories from largest to smallest at the top level only. On older system h will not work and you must use k.
du -sh * | sort
Long Running Processes
Look for long running processes,
Last searches back through the file /var/log/wtmp (or the file designated by the -f flag) and displays a list of all users logged in (and out) since that file was created.
Lastb is the same as last, except that by default it shows a log of the file /var/log/btmp, which contains all the bad login attempts.
Quck String Manipulation
Quick reference of manipulating standout,
echo "some_file_name.txt" | tr "_" " " # result will be "some file name.txt" paste oldName.txt newName.txt > runMe.txt # connects line by line to contents of both files together
Check if a file is corrupt,
# On Ubuntu md5sum /path/to/file # On Solaris digest -a md5 -v /path/to/file