If test is on a line by itself the s switch wont return anything.
//echo $read(info.txt, s, mirc)
Scans the file info.txt for a line beginning with the word mirc and returns the text following the match value.
If you had 2 lines in a file like below it would return on the 2nd line.
mirc
mirc this line returned
Using the s switch would return this line returned and $readn would return 2.