perl question

[Greg Daly]

hey all,
not explicitly linux, but close. i'm trying to match occurences of a
string in perl. problem is, i only want occurences of that string
specifically to ring a true. example, say i have this list:

linux
linus

$input=~/lin/  will give me a TRUE, even though I only want it to ring
true IFF there exists an entry named 'lin'. 

see what i mean? any suggestions? is there a switch i don't know about?
thanks,
-greg