Set user's password in Perl script?

Posted on 2010-08-25
Last Modified: 2012-05-10

I writing a Perl script which will amongst other things create a load of users on a Linux server. I want to be able to have the script set the password for the new users it creates, and email those to the users (I will have an array with the email addresses in).

At the moment I'm struggling to find a way to set passwords in a Perl script - I can see why its difficult but if I can't do this, my plan is significantly less useful than I had hoped!

Any info welcomed. Thanks in advance.

Question by:georgemason
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Expert Comment

ID: 33519952
see an example here
system "sudo /usr/local/bin/ $user $passwd";
or maybe call a shell script to set it passing in args

Expert Comment

ID: 33519967
you can use usermod to change the password.


Author Comment

ID: 33521319
@rockiroads - I've seen that before - but I'm writing the script to run on a Linux box, not as a web app - how would I apply that in my case?

@vikas - tried the following: system("usermod -p $password $reseller");  (where the two variables contain valid strings) and it doesn't error, but doesn't set the pw either

Expert Comment

ID: 33521833
I wonder perhaps you have forgotten to convert the plain text password to hash before passing it to usermod? You can use Crypt::PasswdMD5 available from CPAN for this purpose. The attached code snippet works for me, when executed as root.

The following script works for me (Ubuntu):
use Crypt::PasswdMD5 qw(unix_md5_crypt);
my @salt = ( '.', '/', 0 .. 9, 'A' .. 'Z', 'a' .. 'z' );
sub gensalt {
 my $count = shift;
 my $salt;
 for (1..$count) {
  $salt .= (@salt)[rand @salt];
 return $salt;
$reseller = "abb2";
$password = "xyz2";
my $password_hash = unix_md5_crypt($password, gensalt(8));
system("usermod -p '$password_hash' $reseller");

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Expert Comment

ID: 33521858
I forgot to mention that the above code is based on the example provided by web page.
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Author Comment

ID: 33522710
Sounds very promising - I had forgotten (i.e. didn't know I needed to) hash the pw.

I get this error - do I need to install a perl module?

"Can't locate Crypt/ in @INC "

Expert Comment

ID: 33522922
Yes, the module is available from CPAN archive. Try

sudo perl -MCPAN -e 'install Crypt/PasswordMD5'

For this to work your computer has to have internet access, to download modules from CPAN server. If it is the first time you use CPAN, you may get a lot of questions, in general it is safe to accept default options (just press Enter). See also for more details.

PS. Some Linux distribution offer better way to do the same, Ubuntu and Gentoo at least, maybe other distributions too.
LVL 65

Expert Comment

ID: 33535742
that sample web code is to take in user input of a userid but the password changing code should still be applicable right?

What command are you using right now to create the user?

On your linux o/s do you have the command useradd? If so then that is one way to create users and in there specify the password also.

useradd [-c comment] [-d home_dir]

    [-e expire_date] [-f inactive_time]
    [-g initial_group] [-G group[,...]]
    [-m [-k skeleton_dir] | -M] [-n] [-o] [-p passwd] [-r]
    [-s shell] [-u uid] login

More info on this can be found here


Expert Comment

ID: 33539642
Sorry, I have made a typo in my previous comment. The correct command is

sudo perl -MCPAN -e 'install Crypt::PasswdMD5'
LVL 39

Accepted Solution

Adam314 earned 250 total points
ID: 33605491
If you run your script as root, you can just call passwd directly.  To run your script as root, either use sudo, or actually run it as root.

To run passwd:
    system("echo $new_password | passwd --stdin $user");

To run your script using sudo:
    1) save your script, for example to
    2) Run like:    sudo
        You may be asked for your password

Or, to run as root:
    1) su
        You will be asked for root's password

Author Comment

ID: 33681744
Thanks to you all for your suggestions. In the end the one which (a) worked and (b) was simplest was from Adam314 - so points go to him.

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