bash-4.3$ php -r '$l=strlen(strtok($s=$argv[1],"
> "));while($l)$s=preg_replace("/-/","
> ".str_repeat(" ",--$l-$i)."/",$s,1);echo$s;' -- $'---\n| |\n|_|'

  /
 /
/
| |
|_|