The following script does what is asked (and no more), using only Perl (with one core module) and looking in the current directory only (no recursion):

use strict;
use warnings;
use Cwd;

@ARGV == 1 or die "USAGE: $0 <search_line>\n";

printf "Searching directory '%s' for the line '%s':\n\n",
        Cwd::getcwd(), $ARGV[0];

my $found = 0;

opendir my $dh, '.'
    or die "Unable to open the current directory: $!";

while (my $file = readdir($dh))
{
    if (-f $file)
    {
        open my $fh, '<', $file
            or die "Unable to open file '$file' for reading: $!";

        while (my $line = <$fh>)
        {
            chomp $line;

            if ($line eq $ARGV[0])
            {
                print "Found match in file '$file'\n";
                $found = 1;
                last;
            }
        }

        close $fh
            or die "Unable to close file '$file': $!";
    }
}

closedir $dh
    or die "Unable to close the current directory: $!";

print "No matches found\n" unless $found;
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HTH,