Get the source directory of a Bash script from within the script itself

dirname.min.sh

#!/usr/bin/env bash
__dirname(){ local d s="$0";while [ -h "$s" ];do d="$(cd -P "$(dirname "$s")">/dev/null 2>&1&&pwd)";s="$(readlink "$s" 2>&1)";[[ $s != /* ]]&&s="$d/$s";done;echo "$(cd -P "$(dirname "$s")">/dev/null 2>&1&&pwd)";}

dirname.sh

#!/usr/bin/env bash

__dirname() {
  local d s="$0"

  while [ -h "$s" ]; do
    d="$(cd -P "$(dirname "$s")" >/dev/null 2>&1 && pwd)"
    s="$(readlink "$s" 2>&1)"

    [[ $s != /* ]] && s="$d/$s"
  done

  echo "$(cd -P "$(dirname "$s")" >/dev/null 2>&1 && pwd)"
}