index

Finds the first occurrence of a substring within a string.

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

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

Example 8-20 How to use index to identify the first occurrence of a substring within a string

BEGIN {
         x = "#canyoufindapenguininthisstring?";
         y = "penguin";
         printf("The penguin appears at character %3d\n", index(x, y));
         exit(0)
}