use strict;
use warnings;
use File::Slurp qw(read_dir);
my $phrase = shift;
for my $file (grep { -f } read_dir('./')) {
    open my $fh, '<', $file or die "can not open $file: $!";
    while (<$fh>) {
        print if /$phrase/;
    }
    close $fh;
}