Well, one of your first statements is

    my $row = <$fh>;
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Not only haven't you declared $fh yet, you haven't opened the file at this point. That's something you do later. But when you open the files, you're not checking whether this succeeds.

    my (@col1,@col2);
    my @words = split(//,@col1);
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What's the point of this? @col1 doesn't contain anything, so what you want to split? You're also declaring @col, but not using it.

    @col2 =~ m/$words[$_](\d+)/
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No idea what you want to do, but on the LHS of a =~ you have to have a scalar, not a list or array. Furthermore, since you never put anything in @words, there will be nothing to match here. And even then, $_ is the line you're reading from the file; it probably doesn't contain a number.