Usually you use useradd command to create a new user or update default new user information from command line. However, let us say you want to create a large number of users or if you want to import usernames from a text file. You can use newusers command, which update and create new users in batch.
This is useful at universities or large corporate Linux networks. Adding users in batch saves the time.
This command reads a file of user name and clear-text password pairs and uses this information to update a group of existing users or to create new users. Each line is in the same format as the standard password file.
This command is intended to be used in a large system environment where many accounts are updated at a single time (batch mode). Since username and passwords are stored in clear text format make sure only root can read/write the file. Use chmod command:
# touch /root/batch-user-add.txt
# chmod 0600 /root/batch-user-add.txt
Create a user list as follows. Open file:
# vi /root/batch-user-add.txt
Append username and password:
Now create users in batch:
# newusers /root/batch-user-add.txt