This function returns the portion of haystack which starts at the last occurrence of needle and goes until the end of haystack.
If needle contains more than one character, only the first is used. This behavior is different from that of strchr().
If needle is not a string, it is converted to an integer and applied as the ordinal value of a character.
// get last directory in $PATH
$dir = substr(strrchr($PATH, ":"), 1);
// get everything after last newline
$text = "Line 1\nLine 2\nLine 3";
$last = substr(strrchr($text, 10), 1 );