How To Create Multiple Users Using Shell Script.

In Linux, we create users for multiple purposes, so in Linux, it’s very common to make new users depending on the tasks. So sometimes we need to create more than one user or multiple users. We can’t do it one by one as it would be very time-consuming, so we can use automated scripts to make our tasks easy. 

Method 1: Using Terminal 

In this method, we will not be using any script, we will just use a command to make multiple users in simple steps.

Step 1:  Create a file and list down the names of users in it.

touch /opt/usradd

Step 2: Run for loop given below

for i in `cat /opt/usradd` ; do useradd $i ; done

Step 3: To view the created users simply type “id” in place of useradd

for i in `cat /opt/usradd` ; do id $i ; done

OR

awk - F: '{print $1}' /etc/passwd

Step 4: To give different passwords to each user, interactively use “passwd” in place of useradd.

for i in `cat /opt/usradd` ; do passwd $i ; done

Method 2: Using Shell script

Step 1: First, we have created a text file containing all the names of users. and saved it at a specific location.

create a text file userlist with all the usernames in it.

vim /tmp/userlist

Step 2: After that  we write a script to automate the task.

creating a .sh file to write the script in it.

vim /usr/sbin/createuser.sh

Step 3: We wrote the following script

//execute the Script using a bash shell
#!/bin/bash

//location of the txt file of usernames
userfile=/tmp/userlist 

//extracting usernames from the file one-by-one
username=$(cat /tmp/userlist | tr 'A-Z'  'a-z')

//defining the default password 
password=$username@123

//running loop  to add users
for user in $username
do
       //adding users '$user' is a variable that changes
       // usernames accordingly in txt file.
       useradd $user
       echo $password | passwd --stdin $user
done

//echo is used to display the total numbers of 
//users created, counting the names in the txt 
//file, tail to display the final details of 
//the process on both lines(optional)
echo "$(wc -l /tmp/userlist) users have been created" 
tail -n$(wc -l /tmp userlist) /etc/passwd

Tags used in the script :

• userfile — gave the location of the file with all the usernames it contains.

• username — read the file using ‘cat’, translate all the uppercase letters to lowercase letters, because we never know in what format the user has given the name.

• password — will be your username @123.

• We ran a loop for usernames, following useradd command with all usernames.

• echo — ‘wc -l’ count lines in those files, and prints the number of files.

• tail — Used to check all the details.

Step 4: Give permissions to the script file. u+x, the only user will be able to execute this file 

//here we are giving the executable permission 
//of the file to the user.
chmod u+x /usr/sbin/createuser.sh