As part of the HNG Internship program, we were tasked with creating a bash script named create_users.sh to automate the creation of new users and groups on a Linux system.
Learn more about HNG
Overview
This script, create_users.sh, automates the creation of users and their associated groups, sets up their home directories, generates random passwords, and logs all actions. The script reads from a specified text file containing usernames and group names.
Prerequisites
- The script must be run with root privileges.
- Ensure the input file with usernames and groups is formatted correctly and exists.
Input File Format
Each line in the input file should be formatted as follows:
username;group1,group2,...
Example:
light;sudo,dev,www-data
idimma;sudo
mayowa;dev,www-data
Script Steps
Check Root Privileges:
if [[ $EUID -ne 0 ]]- The script starts by checking if it is being run as the root user.
- This is necessary because creating users and modifying system files requires root privileges.
- This ensures that the script has the necessary permissions to perform its tasks.
Validate Input File:
-
if [[ -z "$1" ]]; then echo "Usage: $0 " >&2 - The script checks if the input file is provided as an argument and whether it exists.
Setup Logging and Password Files:
The script sets up the log file and the password file. It ensures the directories exist and sets appropriate permissions for the password file
-
mkdir -p: Ensures the directories exist. -
> "$LOG_FILE"and> "$PASSWORD_FILE": Create or clear the log and password files. -
chmod 600 "$PASSWORD_FILE": Ensures that only the owner can read the password file, enhancing security.
Generate Passwords:
generate_password() { < /dev/urandom tr -dc A-Za-z0-9 | head -c12- The script defines a function to generate random passwords for the new users.
Log Messages:
log_message() { local message="$1" echo "$(date '+%Y-%m-%d %H:%M:%S') : $message" >> "$LOG_FILE"- The script defines a function to log messages with timestamps.
- This provides a way to track actions performed by the script, useful for auditing and debugging.
Process Each Line:
The script reads and processes each line from the input file, creating users and groups, setting up home directories, generating passwords, and logging actions.
-
IFS=';' read -r username groups: Reads the username and groups from each line. -
username=$(echo "$username" | xargs)andgroups=$(echo "$groups" | xargs): Removes leading/trailing whitespace. -
getent group "$username": Checks if the user's personal group exists; creates it if it doesn't. -
id "$username": Checks if the user already exists. -
password=$(generate_password): Generates a random password for the user. -
useradd -m -g "$username" -s /bin/bash "$username": Creates the user with the specified home directory and personal group. -
echo "$username:$password" | chpasswd: Sets the user's password. -
IFS=',' read -r -a group_array <<< "$groups": Splits the groups into an array. -
groupadd "$group": Creates additional groups if they don't exist. -
usermod -aG "$group" "$username": Adds the user to the additional groups.
Final Message:
log_message "User creation script completed successfully" echo "User creation script completed. Check the log file at $LOG_FILE and passwords at $PASSWORD_FILE."- The script logs a completion message and prints a final status to the console.
- Notifies the user of the script's completion and provides locations for the log and password files.
Usage
Save the script as create_users.sh and make it executable:
chmod +x create_users.sh
Run the script with the user file as an argument:
sudo ./create_users.sh <name-of-text-file>
Logs and Password Storage
- Log File: /var/log/user_management.log contains logs of all actions performed.
- Password File: /var/secure/user_passwords.csv stores the generated passwords securely.
Example User File
Create a file named user_list.txt with the following content:
light;sudo,dev,www-data
idimma;sudo
mayowa;dev,www-data
Run the script
sudo ./create_users.sh user_list.txt
This script ensures that users and groups are created as specified, with appropriate permissions and logging.
Learn More About HNG Internship
The HNG Internship is a remote internship program designed to find and develop the most talented software developers. It offers a stimulating environment for interns to improve their skills and showcase their abilities through real-world tasks.
Top comments (0)