I do not see that error; what is the exact code you have?

sub find_string {
    my ($file, @strings) = @_;
    open my $fh, '<', $file;
    while (<$fh>) {
        for my $string (@strings) {
            return 1 if /\Q$string/;
        }
    }
    die "Unable to find string: @strings";
}

find_string('filename', "testing","link","rd");
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Of course the above should be amended to test that the open worked:

    open my $fh, '<', $file or die "File open fail ($file): $!";
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