Robustly get script's actual directory (bash)

gistfile1.sh

#!/bin/bash
# Put's the script's directory in the $BS variable.
# Follows symlinks, works on mac-os as well as linux etc.
# Move final popd to the end of your script if you want to run your script with the script's directory as the working directory.

BS="${BASH_SOURCE[0]}";RL="readlink";([[ `uname -s`=='Darwin' ]] || RL="$RL -f")
  while([ -h "${BS}" ]) do BS=`$RL "${BS}"`; done
  N="/dev/null";pushd .>$N;cd `dirname ${BS}`>$N;BS=`pwd`;popd>$N

# ... rest of the script ... use ${BS} when referring to this script's directory