246

I need to have the ability to create user accounts on my Linux (Fedora 10) and automatically assign a password via a bash script(or otherwise, if need be).

It's easy to create the user via Bash e.g.:

[whoever@server ]#  /usr/sbin/useradd newuser

Is it possible to assign a password in Bash, something functionally similar to this, but automatically:

[whoever@server ]# passwd newuser
Changing password for user testpass.
New UNIX password:
Retype new UNIX password: 
passwd: all authentication tokens updated successfully.
[whoever@server ]#
5
  • 14
    Why is this offtopic? Commented Feb 28, 2013 at 19:08
  • 24
    I think this question is on topic. One of the strongest trends now is the DevOps attitude of "configuration as code", i e that the platform is created by "programming" a sequence of admin steps that bootstrap the platform. To do user management in script mode is definitely part of this programming. Commented Oct 29, 2013 at 12:08
  • 2
    As a DevOps, I think this is a useful question (with useful answers) but that's with my SysAdmin hat on. It might make more sense to move this to SuperUser. Commented Apr 2, 2014 at 10:53
  • 1
    Similar question: askubuntu.com/q/94060/250556 Commented Aug 31, 2015 at 18:51
  • This can also be solved with an expect script. Commented Jun 26, 2016 at 6:49

20 Answers 20

253

You could also use chpasswd:

echo username:new_password | chpasswd

so, you change password for user username to new_password.

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3 Comments

+1, This is the right tool for the job: $ apropos chpasswd ... chpasswd (8) - update passwords in batch mode
This also works with busybox, whereas passwd does not (there's no --stdin option).
chpasswd must be run with root privileges / sudo
140

You can run the passwd command and send it piped input. So, do something like:

echo thePassword | passwd theUsername --stdin

7 Comments

Bonus of that method is that it's secure (assumed echo is a builtin in the used shell, which it is commonly), at least concerning /proc/.
I had to do echo -e "password\npassword\n" | passwd on 13.04
--stdin has been deprecated in newer Linux systems. Please use chpasswd instead.
@MarkusOrreilly works, but not when using a provisioning tool like Ansible. As @Nybble stated, you should be using chpasswd. So here is what works: echo 'myuser:mypass' | chpasswd. Hope that helps.
I'm surprised no-one has mentioned the reason passwd doesn't make this easy: this approach will put the new password straight into the shell history, unless steps are taken to prevent this. Anyone committed to going this route, should keep this is mind.
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132

I was asking myself the same thing, and didn't want to rely on a Python script.

This is the line to add a user with a defined password in one bash line:

useradd -p "$(openssl passwd -6 $PASS)" $USER
  • Note the double quote to prevent the shell interpreting included special parameters. Namely $ in this case.
  • This uses a SHA-512 hash, specified by the -6 flag. See openssl passwd --help for more options.

Edit: Since c87a7f31a3 the option -crypt is removed. Therefore replaced with -6 flag in the example above.

6 Comments

useradd -p $(openssl passwd -1 $PASS) $USER is more modern, as back-ticks are deprecated and $() is recommended.
An issue I had with this: I had created my user with a shell of zsh, not realizing that at that point zsh hadn't been installed. The password login will fail if you do this, so before you assume this isn't working (it will definitely work on today's Arch and on Debian 7) you might check that on a brand new installation.
useradd -m -p <password> -s /bin/bash <user>, -m Crates home directory, -s specifies users defualt shell, substitute password and user for your needs.
You can also salt the password: useradd -m -p $(openssl passwd -1 -salt $SALT $PASS) . I think this is required on later Ubuntu's.
@Bryson don't use -1 as that one uses MD5, which is not secure anymore. Use -crypt (default at least in OpenSSL 1.1.1).
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82

The code below worked in Ubuntu 14.04. Try before you use it in other versions/linux variants.

# quietly add a user without password
adduser --quiet --disabled-password --shell /bin/bash --home /home/newuser --gecos "User" newuser

# set password
echo "newuser:newpassword" | chpasswd

https://en.wikipedia.org/wiki/Gecos_field The gecos field, or GECOS field is an entry in the /etc/passwd file on Unix, and similar operating systems. It is typically used to record general information about the account or its user(s) such as their real name and phone number. GECOS means General Electric Comprehensive Operating System, which has been renamed to GCOS when GE’s large systems division was sold to Honeywell.

This can be very useful to specify. Setting this string, at least equal to the username, as it makes the user distinguishable, e.g. when they are listed at the login screen of a display manager.

6 Comments

i don't understand --gecos
en.wikipedia.org/wiki/Gecos_field The gecos field, or GECOS field is an entry in the /etc/passwd file on Unix, and similar operating systems. It is typically used to record general information about the account or its user(s) such as their real name and phone number. GECOS means General Electric Comprehensive Operating System, which has been renamed to GCOS when GE’s large systems division was sold to Honeywell.
This was the right answer for me on Debian 8, worked like a charm on my Server setup bash script!
The GECOS field is basically a user description field. Write whatever you want down there.
This also worked when setting a default non-root user in an Alpine Linux container (version 3.18.3).
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37

I liked Tralemonkey's approach of echo thePassword | passwd theUsername --stdin though it didn't quite work for me as written. This however worked for me.

echo -e "$password\n$password\n" | sudo passwd $user

-e is to recognize \n as new line.

sudo is root access for Ubuntu.

The double quotes are to recognize $ and expand the variables.

The above command passes the password and a new line, two times, to passwd, which is what passwd requires.

If not using variables, I think this probably works.

echo -e 'password\npassword\n' | sudo passwd username

Single quotes should suffice here.

2 Comments

Works beautifully in bash. However, if running in sh, then -e option does not work. I found out the hard way that it actually outputs "-e". Luckily, the -e option is not necessary in sh, the escaping is default there. The portable version is to use printf "password\npassword\n" | ... instead.
Perfect answer for ubuntu.
28

The following works for me and tested on Ubuntu 14.04. It is a one liner that does not require any user input.

sudo useradd -p $(openssl passwd -1 $PASS) $USERNAME

Taken from @Tralemonkey

Comments

21

Single liner to create a sudo user with home directory and password.

useradd -m -p $(openssl passwd -1 ${PASSWORD}) -s /bin/bash -G sudo ${USERNAME}

2 Comments

Awesome. Works well in deployment script
Works for me if sudo is replaced by wheel as on RHEL
11

You can use the -p option.

useradd -p encrypted_password newuser

Unfortunately, this does require you to hash the password yourself (where passwd does that for you). Unfortunately, there does not seem to be a standard utility to hash some data so you'll have to write that yourself.

Here's a little Python script I whipped up to do the encryption for you. Assuming you called it pcrypt, you would then write your above command line to:

useradd -p $(pcrypt ${passwd}) newuser

A couple of warnings to be aware of.

  1. While pcrypt is running, the plaintext will be visible to any user via the ps command.
  2. pcrypt uses the old style crypt function - if you are using something more moderns like an MD5 hash, you'll need to change pcrypt.

and here's pcrypt:

#!/usr/bin/env python

import crypt
import sys
import random

saltchars = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"

def salt():
    return random.choice(saltchars) + random.choice(saltchars)

def hash(plain):
    return crypt.crypt(arg, salt())

if __name__ == "__main__":
    random.seed()
    for arg in sys.argv[1:]:
        sys.stdout.write("%s\n" % (hash(arg),))

3 Comments

Thanks R Klatchko, That should work. I can't believe I didn't know about the -p option. I can take care of hashing myself:)
perl -e 'print crypt($ARGV[0], "password")' 'mypassword'
Can you explain a little bit, how I would be able to use the password and not the hashed password later?
11

--stdin doesn't work on Debian. It says:

`passwd: unrecognized option '--stdin'`

This worked for me:

#useradd $USER
#echo "$USER:$SENHA" | chpasswd

Here we can find some other good ways:

1 Comment

This is the proper way to do it, and the only way officially supported by the maintainers of the shadow suite. See this bug report.
5

You can use expect in your bash script.

From http://www.seanodonnell.com/code/?id=21

#!/usr/bin/expect 
######################################### 
#$ file: htpasswd.sh 
#$ desc: Automated htpasswd shell script 
######################################### 
#$ 
#$ usage example: 
#$ 
#$ ./htpasswd.sh passwdpath username userpass 
#$ 
###################################### 

set htpasswdpath [lindex $argv 0] 
set username [lindex $argv 1] 
set userpass [lindex $argv 2] 

# spawn the htpasswd command process 
spawn htpasswd $htpasswdpath $username 

# Automate the 'New password' Procedure 
expect "New password:" 
send "$userpass\r" 

expect "Re-type new password:" 
send "$userpass\r"

Comments

5

I know I'm coming at this years later, but I can't believe no one suggested usermod.

usermod --password `perl -e "print crypt('password','sa');"` root

Hell, just in case someone wants to do this on an older HPUX you can use usermod.sam.

/usr/sam/lbin/usermod.sam -F -p `perl -e "print crypt('password','sa');"` username

The -F is only needed if the person executing the script is the current user. Of course you don't need to use Perl to create the hash. You could use openssl or many other commands in its place.

Comments

5

I've tested in my own shell script.

  • $new_username means newly created user
  • $new_password means newly password

For CentOS

echo "$new_password" | passwd --stdin "$new_username"

For Debian/Ubuntu

echo "$new_username:$new_password" | chpasswd

For OpenSUSE

echo -e "$new_password\n$new_password" | passwd "$new_username"

Comments

3

Here is a script that will do it for you .....

You can add a list of users (or just one user) if you want, all in one go and each will have a different password. As a bonus you are presented at the end of the script with a list of each users password. .... If you want you can add some user maintenance options

like:

chage -m 18 $user
chage -M 28 $user

to the script that will set the password age and so on.

=======

#!/bin/bash

# Checks if you have the right privileges
if [ "$USER" = "root" ]
then

# CHANGE THIS PARAMETERS FOR A PARTICULAR USE
PERS_HOME="/home/"
PERS_SH="/bin/bash"

   # Checks if there is an argument
   [ $# -eq 0 ] && { echo >&2 ERROR: You may enter as an argument a text file containing users, one per line. ; exit 1; }
   # checks if there a regular file
   [ -f "$1" ] || { echo >&2 ERROR: The input file does not exists. ; exit 1; }
   TMPIN=$(mktemp)
   # Remove blank lines and delete duplicates 
   sed '/^$/d' "$1"| sort -g | uniq > "$TMPIN"

   NOW=$(date +"%Y-%m-%d-%X")
   LOGFILE="AMU-log-$NOW.log"

   for user in $(more "$TMPIN"); do
      # Checks if the user already exists.
      cut -d: -f1 /etc/passwd | grep "$user" > /dev/null
      OUT=$?
      if [ $OUT -eq 0 ];then
         echo >&2 "ERROR: User account: \"$user\" already exists."
         echo >&2 "ERROR: User account: \"$user\" already exists." >> "$LOGFILE"
      else
         # Create a new user
         /usr/sbin/useradd -d "$PERS_HOME""$user" -s "$PERS_SH" -m "$user"
         # passwdgen must be installed
         pass=$(passwdgen -paq --length 8)
         echo $pass | passwd --stdin $user
         # save user and password in a file
         echo -e $user"\t"$pass >> "$LOGFILE"
         echo "The user \"$user\" has been created and has the password: $pass"
      fi
   done
   rm -f "$TMPIN"
   exit 0
else
   echo >&2 "ERROR: You must be a root user to execute this script."
   exit 1
fi

===========

Hope this helps.

Cheers, Carel

Comments

3

The solution that works on both Debian and Red Hat. Depends on perl, uses sha-512 hashes:

cat userpassadd
    #!/usr/bin/env bash

    salt=$(cat /dev/urandom | tr -dc A-Za-z0-9/_- | head -c16)
    useradd -p $(perl -e "print crypt('$2', '\$6\$' . '$salt' . '\$')") $1

Usage:

userpassadd jim jimslongpassword

It can effectively be used as a one-liner, but you'll have to specify the password, salt and username at the right places yourself:

useradd -p $(perl -e "print crypt('pass', '\$6\$$salt\$')") username

Comments

2

From IBM (https://www.ibm.com/support/knowledgecenter/ssw_aix_61/com.ibm.aix.cmds1/chpasswd.htm):

Create a text file, say text.txt and populate it with user:password pairs as follows:

user1:password1
user2:password2
...
usern:passwordn

Save the text.txt file, and run

cat text.txt | chpassword

That's it. The solution is (a) scalable and (b) does not involve printing passwords on the command line.

Comments

1

Tralemonkey's solution almost worked for me as well ... but not quite. I ended up doing it this way:

echo -n '$#@password@#$' | passwd myusername --stdin

2 key details his solution didn't include, the -n keeps echo from adding a \n to the password that is getting encrypted, and the single quotes protect the contents from being interpreted by the shell (bash) in my case.

BTW I ran this command as root on a CentOS 5.6 system in case anyone is wondering.

1 Comment

good catch, not sure how others managed to get it working with the newline thingy.
1
{ echo $password; echo $password; } | passwd $username 

1 Comment

Whilst this may theoretically answer the question, it would be preferable to include the essential parts of the answer here.
1

For RedHat / CentOS here's the code that creates a user, adds the passwords and makes the user a sudoer:

#!/bin/sh
echo -n "Enter username: "
read uname

echo -n "Enter password: "
read -s passwd

adduser "$uname"
echo $uname:$passwd | sudo chpasswd

gpasswd wheel -a $uname

Comments

1

usage: ./my_add_user.sh USER PASSWD

code:

#!/bin/bash
# my_add_user.sh

if [ "$#" -lt 2 ] 
 then
       echo "$0 username passwd"
       exit
fi

user=$1
passwd=$2

useradd $user -d /data/home/$user  -m  ;
echo $passwd | passwd $user --stdin;

Comments

0

Kindly run below script with sudo permission for creating a user by script.

Note: This script supports all linux OSs like Redhat, Centos, Ubuntu, suse, kali, Arch, Bitname, BSD....etc

#!/bin/bash
#author: bablish jaiswal
#purpos: Linux user creation with a storng password
clear
#echo "Hi, I am a function to create sudo user with strong password. Kindly share following information"
echo -e "\n\n\n"
printf "\e[6;33mHi, I am a function to create sudo user with a strong password. Kindly share following information\e[0m";echo
read -p "user name:- " name #input name
read -p "complete path for $name home directory? example: /home/$name :- " home #user home path
( useradd  -m -d $home $name -s /bin/bash ) > /dev/null 2>&1
pass=$(cat /dev/urandom |tr -dc "[[:graph:]]" |head -c16)
(echo -e "$pass\n$pass" | passwd $name ) > /dev/null 2>&1
echo " "
printf "\e[6;33m-----------------------------Copy below credentials-------------------------\e[0m";echo
echo -e "User:- $name\nHomeDir:- $home\npassword:- $pass"
#svalue=$(cat /etc/sudoers |grep -i root |grep -i all|tail -n1 |awk '{$1=""}1')
svalue=$(cat /etc/sudoers |grep -i root |grep -i all|tail -n1 |awk '{print $2}')
echo "${name} ${svalue} NOPASSWD:ALL" >> /etc/sudoers && echo “Remark:- User $name is a sudo user”

Comments

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