rindex

Finds the last occurrence of a specific substring within a string.

int rindex(const char * str, const char * substr[, int start])

The rindex function finds the position of the last occurrence of a substring, substr, in a string, str, starting at an optional position, start. If the specified value of start position is less than 0, it's implicitly set to 0. If the string is an empty string, rindex returns 0. If no match is found for the substring within the string, rindex returns -1.

Example 8-39 How to use rindex to identify the last occurrence of a substring within a string

BEGIN {
         x = "#findthelastpenguininthepenguinstring!";
         y = "penguin";
         printf("The last penguin appears at character %3d\n", rindex(x, y));
         exit(0)
 }