cheat sheets.

File in Use?
  lsof | grep <file>  (case-sensitive)

Check the dependecy of a binary file:
  objdump -p a.exe | grep 'DLL Name'

To run a process in the background, regardless of whether the terminal window is
closed:
  nohup <some command> &

  eg. nohup ruby /u/app/qbglc/current/script/runner -e development 'load
  "/u/app/qbglc/current/script/app/some_script.rb"' &
  
Disk Usage:
$ du -sh *
$ df -h