Write script to create multiple users with pre-defined passwords

Question

So I would like to make a script that create users from users.txt running

useradd -m -s /bin/false users_in_the_users.txt

and fill the password from passwords.txt twice (to confirm the passwords)

This is the script

#!/bin/bash

# Assign file descriptors to users and passwords files
exec 3< users.txt
exec 4< passwords.txt
exec 5< passwords.txt

# Read user and password
while read iuser <&3 && read ipasswd <&4 ; do
  # Just print this for debugging
  printf "\tCreating user: %s with password: %s\n" $iuser $ipasswd
  # Create the user with adduser (you can add whichever option you like)
  useradd -m -s /bin/false $iuser
  # Assign the password to the user, passwd must read it from stdin
  passwd $iuser
done

The problem is, it does not fill the passwords. And 1 more thing, I want the script to fill the passwords twice.

Any suggestions?

mklement0 · Accepted Answer · 2015-03-07 21:16:31Z

3

You have to supply the password on stdin. Replace:

passwd $iuser

with:

passwd "$iuser" <<<"$ipasswd
$ipasswd"

or, as suggested by mklement0:

passwd "$iuser" <<<"$ipasswd"$'\n'"$ipasswd"

The incantation <<< creates a here-string. The string that follows the <<< is provided as standard in to the command which precedes the <<<. In this case we provide the two copies of the password that the passwd command wants.

(The script reads these passwords from a plain text file. I will assume that your situation is some special case for which this is not as dangerous as it normally would be.)

edited Mar 7, 2015 at 21:16

mklement0

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answered Mar 7, 2015 at 20:09

John1024

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9 Comments

Baba Mok Over a year ago

Thank you. I tried and I get this error Enter new UNIX password: Retype new UNIX password: Sorry, passwords do not match passwd: Authentication token manipulation error passwd: password unchanged

mklement0 Over a year ago

@BabaMok: That suggests that you haven't entered the here-string correctly; perhaps try on a single line with passwd "$iuser" <<<"$ipasswd"$'\n'"$ipasswd". Also, just to state what may be obvious to some: this must be run as root (with sudo).

Baba Mok Over a year ago

Thank you so much both of you. It works! I changed from passwd $iuser to passwd "$iuser"<<<"$ipasswd"$'\n'"$ipasswd" and it works! Thank you again guys

John1024 Over a year ago

@mklement0 Thanks. I updated the answer with your suggestions.

John1024 Over a year ago

@mklement0 Just fine. And your answer got my +1.

|

Community · Accepted Answer · 2017-05-23 11:46:16Z

John1024's answer is the correct one - his warning about reading passwords from plain-text files bears repeating.

Let me show the solution in context, without the file-descriptor acrobatics (exec 3<, ...):

#!/bin/bash

# NOTE: Be sure to run this script with `sudo`.

# Read user and password
while read iuser ipasswd; do

  # Just print this for debugging.
  printf "\tCreating user: %s with password: %s\n" $iuser $ipasswd

  # Create the user with adduser (you can add whichever option you like).
  useradd -m -s /bin/false $iuser

  # Assign the password to the user.
  # Password is passed via stdin, *twice* (for confirmation).
  passwd $iuser <<< "$ipasswd"$'\n'"$ipasswd"

done < <(paste users.txt passwords.txt)

paste users.txt passwords.txt reads corresponding lines from the two files and puts them on a single line, separated with \t.
The result is piped to stdin via a process substitution (<(...)).
This allows read to read from a single source.
$\n is an ANSI C-quoted string that produces a (literal) newline.

Manish Sakariya · Accepted Answer · 2016-10-27 17:09:32Z

0

   #! /bin/bash

   for i in {1..100}
    do
      `sudo mkdir -p /root/Desktop/userm$i`
      `sudo useradd -m -d /root/Desktop/userm$i -s /bin/bash userm$i`
       echo "userm$i:userm$i" | chpasswd

   done

this will create 100 users.
user name will be (userm1-userm100).
home directory will be /root/Desktop/(userm1-user100)
password will be (userm1-userm100)

answered Oct 27, 2016 at 17:09

Manish Sakariya

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Comments

GhostCat · Accepted Answer · 2017-09-06 12:34:03Z

0

Instead of using this line:

useradd -m -s /bin/false $iuser

Try this one:

useradd -m -s /bin/false -p $ipasswd $iuser

You don't actually need this:

passwd $iuser <<< "$ipasswd"$'\n'"$ipasswd"

edited Sep 6, 2017 at 12:34

GhostCat

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answered Sep 6, 2017 at 12:10

user8176207

Comments

linux.cnf · Accepted Answer · 2021-02-21 13:40:04Z

0

Kindly run the below script.

#!/bin/bash
#purpose: bash script to create multiple users with pre-defined passwords at once.
#Read_Me: The import file should be in two columns, first users name and second passwords.
#author: Bablish Jaiswal
#contact: [email protected]

    read -p "Kindly import/type Users Name-password file with location:- " creation_info
    cat $creation_info |while read i p
    do
            ( useradd  $i   &&  echo -e "${p}\n${p}" |  passwd  $i )  > /dev/null 2>&1 && echo $user ${i} created and password is ${p} || echo ${i} failed 
    done

answered Feb 21, 2021 at 13:40

linux.cnf

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