So I won't talk about the pattern part.
The match operator is called with the m/OHAI/ pattern, or just /OHAI/ . if you don't specify something to match against, perl will use our good friend $_ , so when you iterate through a file, you are probably ok with this convention:
$yay = $_ if /say/ ;
Sometimes we don't want to match against $_, and we'd like to parse another var. That's ok, we use the =~ operator, which tells 'm' the variable to do the match with. But there is where I get somewhat puzzled sometimes, because if I want to assign the match to a var, you have to chain it
$match = $string =~ /yay/;
And that doesn't do what we usually want.
I've written this little test script to help me remember how to do proper matchings, and get the info I want from them.