The problem with your piece of code is that the regex you tried to build include "/" and the delimiters are also "/". This is going to work:

chomp($value = <STDIN>); 
if ($value =~ m#(0[1-9]|[12][0-9]|3[01])[-/.](0[1-9]|1[012])[- /.](\d\
+d\d\d)#) { 
    print "date"; 
} else { 
    print $value; print "not a date"; 
}
[download]

Here I used alternative delimiters by using m## syntax. You may read more about it at section "Regexp Quote-Like Operators" in perlop.

And while we're at the issue of validating dates, your code may work for dates like "01/02/2007" and recognize "32/04/2007" as bad, but it will accept things like "29/02/2007" and the like. If you want correctness and minimum effort, you can use some CPAN module to check it out for you. For instance, using DateTime::Format::Strptime, you may write code like this:

se DateTime::Format::Strptime;

my $dt_format = DateTime::Format::Strptime->new(pattern => "%d-%m-%Y")
+; 

sub val_date {
    my $dt = shift;
    $dt =~ s|[./]|-|g; # '.' and '/' become '-' for simplicity
    return $dt_format->parse_datetime($dt);
}

my $s = '01-02-2007';
my $dt = val_date($s);
if ($dt) {
    print "valid date\n";
} else {
    print "not a date\n";
}
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As an extra bonus, the return of val_date gives you a DateTime object which is much better to handle than just a string.

What problem do you have with that? My problem is that I can't read your post - the code is all messed up.

After composing a post and hitting [preview], a line is displayed below the rendered output of the composed text, reading:

If something looked unlike you expected it to you might need to check out Writeup Formatting Tips.

Do so, please.

--shmem

_($_=" "x(1<<5)."?\n".q·/)Oo.  G°\        /
                              /\_¯/(q    /
----------------------------  \__(m.====·.(_("always off the crowd"))."·
");sub _{s./.($e="'Itrs `mnsgdq Gdbj O`qkdq")=~y/"-y/#-z/;$e.e && print}

Looks like your code should read:

chomp($value = <STDIN>);
if($value =~ /(0[1-9]|[12][0-9]|3[01])[- /.](0[1-9]|1[012])[- /.] \d\d
+\d\d)/) {
    print "date";
}else{
    print $value;
    print "not a date";
}
[download]

I notice there's a literal space between [- /.] and \d\d\d\d, which may not be what you intended. That's if I've correctly deciphered your very poorly formatted post.

#!/usr/bin/perl

die "I'm a lazy git who wants help but can't be bothered to explain my
+ problem properly. Kick me!\n"
[download]