How about: 

#!/usr/bin/perl

while(<DATA>) {
        chomp;
        if( /\A[\w]{3}_\w+_ear\Z/ ) {  
                print "$_ matches \n";
        }
        else {
                print "no joy for $_ \n";
        }
}

__DATA__
ab_wehave_noear
abc_test_ear
abc_test_two_ear
abcc_test_ear

[download]
which prints: 
no joy for ab_wehave_noear
abc_test_ear matches
abc_test_two_ear matches
no joy for abcc_test_ear

[download]
I realize your problem definition said "characters" not "word thingies". I'm confident you can munge it to match your expected input range.


Be Appropriate && Follow Your Curiosity

In reply to Re: Help with form validation regex by mikeraz
in thread Help with form validation regex by perlnewb123

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