This isn't a regex, but I don't think anyone mentioned it. 
my @letters = qw(abc cba cab bab blab);
for (@letters) {
    if(join('', sort split //, $_) eq "abc") {print "$_ matched\n"}
    else {print "$_ didn't match\n"}
}

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(My initial thought was to add up the ord() values of the characters. That would work too, but wouldn't be as concise since there isn't a reduce operator in Perl 5.)

In reply to Re: REgular expression to check the string that allows "a","b" and "c" to occur only once in any order. by AK108
in thread REgular expression to check the string that allows "a","b" and "c" to occur only once in any order. by isha

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