The Bourne-Again SHell.
find * | xargs cat: cat contents of files found
du -ch *: show human-readable sizes of files and display total size
lsof -n -iTCP:$PORT | grep LISTEN: show who is listening to certain port (Mac OS X)
Use column to print things nicely:
shocco.sh is a documentation for Bash written in a literate programming style.
man bash or bashinfo bash or Bash Reference Manual