bourne shell canonical readlink

canonical_readlink

# solve the missing `readlink -f` option on OSX
canonical_readlink()
{
  cd `dirname $1`;
  __filename=`basename $1`;
  if [ -h "$__filename" ]; then
    canonical_readlink `readlink $__filename`;
  else
    echo "`pwd -P`/$__filename";
  fi
}