if ( /^[brc]at$/ ) {  # match "bat", "rat", or "cat"
    print "It's an animal\n";
    if ( /^b/ ) {
        print "... and it flies!\n";
    }
}

##</code><code>##

if ( /^[brc]at$/ ) {
    print "It's an animal\n";
}
if ( /^b/ ) {
    print "... and it flies!\n";
}