It's worth noting that this'll only work where the password is encrypted using the inbuilt crypt(3) format. Some systems now use stronger protection than this, such as the MD5 algorithm.

You may be interested in the following CPAN modules too.. Crypt-RandPasswd for creating random pronouncable passwords, and Data::Password for evaluating how strong a password is.

Update: Changed 'encryption' to 'protection' and 'algorithm' thanks to nothingmuch reminding me MD5 isn't actually an encryption.

Generating password for users? Isn't that supposed to be done with rand()?

Something like this:

my @possible_chars = 'a'..'z';
my $passw = '';
$passw .= $possible_chars[int rand scalar @possible_chars] for(1..8);
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Either that, or I have totally misunderstood your question. Sorry if that is the case.