open(INPUT, "data.txt") || die "Error opening 'keywd.txt'\n";
             ^^^^----------- wtf? -------------^^^^^
[download]

Same here. You use 3 argument open here, you should do the same in the previous open, just to be consistent:

open(FH, '<', "keywd.txt") || die "Error opening 'data.txt'\n";
[download]

open(FH, '<', "keyword.txt") || die "Error opening 'keyword.txt': $!\n
+";
                   ^^-- sic!     error message in here -----------^^
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to get the error (No such file, permission denied, ...) along.

You can chomp an entire array

chomp(my @data = <INPUT>);
[download]

And you do a chomp on $element, but not on the contents of the @keywd array. So, your $element never matches e.g. analysis\n. <update> You require there be a newline in $element - but there isn't one, 'twas chomped off. </update>The other way round there would have been a match.

BTW, your code formatting is pretty messy..

--shmem

_($_=" "x(1<<5)."?\n".q·/)Oo.  G°\        /
                              /\_¯/(q    /
----------------------------  \__(m.====·.(_("always off the crowd"))."·
");sub _{s./.($e="'Itrs `mnsgdq Gdbj O`qkdq")=~y/"-y/#-z/;$e.e && print}