Category: Utility Scripts
Author/Contact Info Terrence Hamilton - ersatz@netspace.net.au
Description: This script will generate a 9 character random password, consisting of 3 uppercase characters, 3 lowercase characters & 3 numbers. 
#!/usr/bin/perl

$uppercase = join '', $uppercase, A..Z;
$lowercase = join '', $lowercase, a..z;
$numbers = join '', $numbers, 0..9;

for ($i = 0; $i < 3; $i++) {
  $tmp = join '', $tmp, substr $uppercase, int rand length $uppercase,
+ 1;
  $tmp = join '', $tmp, substr $lowercase, int rand length $lowercase,
+ 1;
  $tmp = join '', $tmp, substr $numbers,  int rand length $numbers, 1;
};

while (length $tmp) {
  $password = join '', $password, substr $tmp, int rand length $tmp, 1
+, '';
};

print "Password: $password\n";
Replies are listed 'Best First'.
Re: Random Password Generator
by radiantmatrix (Parson) on Jul 05, 2005 at 14:04 UTC
    Hm. Some flaws, like forcing a particular pattern, not using printable chars outside of A-Za-z0-9, etc. Mostly, though, reinventing a well-solved wheel. 
    use Crypt::RandPasswd;
print 'Password: ',Crypt::RandPasswd->chars(9,9), "\n";

    [download]
    The above generates a 9-char random password using Crypt::RandPasswd. If limiting the chars used, etc, is desired, read the POD for that module, as it explains how to restrict character space and other features.

    If you're on a UNIX system, importing Crypt::Random will give you access to a better PRNG (using /dev/random or the EGD) that you can hand off to Crypt::RandPasswd. If you're not on UNIX, you can either install a version of EGD for your platform, or try using Crypt::Random::ISAAC - secure random number generator (which, admittedly, is something I wrote for solving the cryptographic randomness issue in pure Perl). EGD (or /dev/random) with Crypt::Random is by far the better choice, if it is available to you (better tested, more mature, etc.)

    Larry Wall is Yoda: there is no try{}
    The Code that can be seen is not the true Code
[reply]
[d/l]
Re: Random Password Generator
by ihb (Deacon) on Jul 03, 2005 at 00:35 UTC 

    use String::Random qw/ random_string /;
use List::Util qw/ shuffle /;

print random_string(join '', shuffle((qw/ c C n /) x 3));

    [download]

    ihb

    See perltoc if you don't know which perldoc to read!

[reply]
[d/l]
Re: Random Password Generator
by sh1tn (Priest) on Jul 02, 2005 at 14:08 UTC 
    print+('a'..'A','A'..'1','0'..'9')[int rand(64)]for 1..9

    [download]


[reply]
[d/l]

      Pugs Perl6 version: print ('a'..'z','A'..'Z',0..9).pick for 0..8;


      ___________
      Eric Hodges
[reply]
[d/l]
Re: Random Password Generator
by Anonymous Monk on Jul 01, 2005 at 07:51 UTC
    That is very nice and simple unlike a lot of other ones i have seen here at the monastery. *THUMBS UP*
[reply]
      It is simpler than many, but still unecessarily complicated, because of the amount of repeated code.

      Presuming you want 3 each of the lowercase, uppercase, and digits, you can simplify the code to: 

      my @ranges = ([a..z]) x 3, ([A..Z]) x 3, ([0..9]) x 3;
my $password;
while (@ranges) {
  $range = splice @ranges, rand @ranges, 1; # random pick
  $password .= $range->[rand @$range]; # random pick from the range
}

      [download]
      The whole thing of $password = join "", $password, ... in the original post is definitely worth unlearning if nothing else. {grin}

      -- Randal L. Schwartz, Perl hacker
      Be sure to read my standard disclaimer if this is a reply.

[reply]
[d/l]
[select]

        Or even simpler: 

        @chr = (0..9,'A'..'Z','a'..'z');
print @chr[rand @chr] for 1..9;

        [download]

        but you don't get anymore the 3-3-3 pattern, which IMHO, isn't a big deal anyway.

[reply]
[d/l]
        This was actually a little experiment. I know the more practical way would be to use arrays, like in your post. I was just trying to find the best way to do it using only strings. :o)
[reply]
        I'm the original anon poster.. (-- I'll make an account one of these days) and umm.. what variable in your improvement is the password at the end? I can't seem to work it out. I know, I know. I'm dumb.
[reply]

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