In this article, we'll walk through a bash script that reads user information from a text file, creates users and their groups, sets up home directories, generates random passwords, logs actions, and stores passwords securely.
Bash Script: create_users.sh
#!/bin/bash
# Define file paths
LOG_FILE="/var/log/user_management.log"
PASSWORD_FILE="/var/secure/user_passwords.txt"
INPUT_FILE=$1
# Ensure secure directory for passwords
mkdir -p /var/secure
chmod 700 /var/secure
# Function to generate random password
generate_password() {
tr -dc A-Za-z0-9 </dev/urandom | head -c 12
}
# Ensure log file exists
touch $LOG_FILE
chmod 644 $LOG_FILE
# Ensure password file exists
touch $PASSWORD_FILE
chmod 600 $PASSWORD_FILE
# Read input file
if [[ ! -f "$INPUT_FILE" ]]; then
echo "Input file not found!" | tee -a $LOG_FILE
exit 1
fi
# Process each line in the input file
while IFS=";" read -r username groups; do
# Trim whitespaces
username=$(echo $username | xargs)
groups=$(echo $groups | xargs)
# Check if user already exists
if id -u "$username" >/dev/null 2>&1; then
echo "User $username already exists. Skipping." | tee -a $LOG_FILE
continue
fi
# Create personal group for the user
groupadd "$username"
# Create user with personal group
useradd -m -g "$username" "$username"
if [[ $? -ne 0 ]]; then
echo "Failed to create user $username." | tee -a $LOG_FILE
continue
fi
# Create additional groups and add user to them
IFS=',' read -ra ADDR <<< "$groups"
for group in "${ADDR[@]}"; do
group=$(echo $group | xargs)
if ! getent group "$group" >/dev/null; then
groupadd "$group"
fi
usermod -aG "$group" "$username"
done
# Generate random password and set it
password=$(generate_password)
echo "$username:$password" | chpasswd
# Log user creation
echo "Created user $username with groups $groups." | tee -a $LOG_FILE
echo "$username,$password" >> $PASSWORD_FILE
done < "$INPUT_FILE"
echo "User creation process completed." | tee -a $LOG_FILE
When working as a SysOps engineer, managing user accounts and groups is a routine but crucial task. Automating this process not only saves time but also reduces the potential for errors.
Features:
1.Input File Processing
: The script takes a text file where each line contains a username and a list of groups, separated by a semicolon (;). Example:
light;sudo,dev,www-data
idimma;sudo
mayowa;dev,www-data
2.User and Group Creation: For each user, the script creates a personal group with the same name as the username and adds the user to the specified groups.
3.Home Directory Setup: Home directories are created automatically with appropriate permissions.
4.Random Password Generation: A secure random password is generated for each user.
5.Logging Actions: All actions performed by the script are logged to /var/log/user_management.log
6.Secure Password Storage: Usernames and passwords are stored in /var/secure/user_passwords.txt with restricted access permissions.
Script Breakdown:
1.File Paths and Secure Directory Setup:
LOG_FILE="/var/log/user_management.log"
PASSWORD_FILE="/var/secure/user_passwords.txt"
INPUT_FILE=$1
mkdir -p /var/secure
chmod 700 /var/secure
2.Random Password Generation Function:
generate_password() {
tr -dc A-Za-z0-9 </dev/urandom | head -c 12
}
3._Log and Password File Initialization:
_
touch $LOG_FILE
chmod 644 $LOG_FILE
touch $PASSWORD_FILE
chmod 600 $PASSWORD_FILE
4.Processing the Input File:
if [[ ! -f "$INPUT_FILE" ]]; then
echo "Input file not found!" | tee -a $LOG_FILE
exit 1
fi
while IFS=";" read -r username groups; do
username=$(echo $username | xargs)
groups=$(echo $groups | xargs)
if id -u "$username" >/dev/null 2>&1; then
echo "User $username already exists. Skipping." | tee -a $LOG_FILE
continue
fi
groupadd "$username"
useradd -m -g "$username" "$username"
if [[ $? -ne 0 ]]; then
echo "Failed to create user $username." | tee -a $LOG_FILE
continue
fi
IFS=',' read -ra ADDR <<< "$groups"
for group in "${ADDR[@]}"; do
group=$(echo $group | xargs)
if ! getent group "$group" >/dev/null; then
groupadd "$group"
fi
usermod -aG "$group" "$username"
done
password=$(generate_password)
echo "$username:$password" | chpasswd
echo "Created user $username with groups $groups." | tee -a $LOG_FILE
echo "$username,$password" >> $PASSWORD_FILE
done < "$INPUT_FILE"
echo "User creation process completed." | tee -a $LOG_FILE
This script ensures efficient user management and enhances security through automated processes. For more insights, explore further learning opportunities, check out the HNG Internship and HNG Premium website. You won't regret it
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