Learning AWK Programming

RLENGTH and RSTART

The match function searches for a given string/pattern/regular expression in the input string and returns a positive value when a successful match occurs. It sets the two special variables, RSTART and RLENGTH, that indicate where a regular expression begins and ends:

• RSTART: This stores the starting location of the search string/pattern
• RLENGTH: This stores the length of the search string/pattern

The contents of the RLENGTH or RSTART variable are set/changed when the match function is invoked.

In the following example, we use the match function to search for a pattern and print all that is present before and after the pattern—as well as the pattern itself, separately—as follows:

$ vi match.awkBEGIN     {    regex="Singh"; } ...