rindex

See the current Perl documentation for rindex.

Here is our local, out-dated (pre-5.6) version:

rindex - right-to-left substring search

rindex STR,SUBSTR,POSITION

rindex STR,SUBSTR

Works just like index except that it returns the position of the LAST occurrence of SUBSTR in STR. If POSITION is specified, returns the last occurrence at or before that position.