use strict;
use warnings;

my $string = shift;

if ( $string =~ /received 486 response/ ) {
    print "matched $string\n";
}
else {
    print "did not match $string\n";
}

##</code><code>##

my @array = (
    "received 480 response",
    "received 485 response",
    "received 486 response",
    "received 487 response"
);

for (@array) {
    if ( $_ =~ /received 486 response/ ) {
        print "matched $_\n";
    }
    else {
        print "did not match $_\n";
    }
}

________________________________________________

Output is:
F:\>script.pl
did not match received 480 response
did not match received 485 response
matched received 486 response
did not match received 487 response