normalize_path() {
	eval "NORMALIZED_PATH=$1"
	NORMALIZED_PATH=`php -r "echo realpath('$NORMALIZED_PATH');"`
}

http://andy.wordpress.com/2008/05/09/bash-equivalent-for-php-realpath/

the os x version of realpath works differently than the linux version; the following allows you to attain the same functionality in a shell on os x as `readlink -f $0` on a standard linux dist.

Relative to Absolute Path Conversion

path, Bash, mac

Bash