use warnings;
use strict;

my @ids = qw( john james );
my $permission = get_data( map { "^$_" } @ids );
print "$permission\n";

$permission = get_data( map { q{"\b} . $_ . q{\b"} } @ids );
print "$permission\n";

sub get_data {
    my (@patterns) = @_;
    my $permission;
    for (@patterns) {
        $permission .= qx( grep $_ /etc/passwd );
    }
    return $permission;
}