User Management in Linux using a bash script

# Check if script is run with sudo
if [ “$(id -u)“ != “0” ]; then
echo “This script must be run with sudo. Exiting…”
exit 1
fi

# Redirect stdout and stderr to log file
exec > >(tee -a “$LOG_FILE“) 2>&1
echo “Executing script… (note that this line will be logged twice)” | tee -a $LOG_FILE

# Check if an argument was provided
if [ $# -eq 0 ]; then
echo “No file path provided.”
echo “Usage: $0 <user-data-file-path>”
exit 1
fi

# Check if the user’s data file exists
if [ ! -e “$USERS_FILE“ ]; then
echo “The provided user’s data file does not exist: $USERS_FILE“
exit 1
fi

# Function to check if a package is installed
is_package_installed() {
dpkg -s “$1“ >/dev/null 2>&1
}

# Check if openssl is installed
if ! is_package_installed openssl; then
echo “openssl is not installed. Installing…”
sudo apt-get update
sudo apt-get install -y openssl
fi

# Check if pwgen is installed
if ! is_package_installed pwgen; then
echo “pwgen is not installed. Installing…”
sudo apt-get update
sudo apt-get install -y pwgen
fi

# Create the directory where the user’s password file will be stored
sudo mkdir -p “$PASSWORD_FILE_DIRECTORY“

# load the content of the users.txt file into an array: lines
mapfile -t lines < “$USERS_FILE“

# loop over each line in the array
for line in “${lines[@]}“; do
# Remove leading and trailing whitespaces
line=$(echo “$line“ | xargs)

# Split line by ‘;’ and store the second part
IFS=‘;’ read -r user groups <<< “$line“

# Remove leading and trailing whitespaces from the second part
user=$(echo “$user“ | xargs)
groups=$(echo “$groups“ | xargs)

# Check if user exists
if id “$user“ &>/dev/null; then
echo “User $user already exists. Skipping creation.”
continue
fi

# Generate a 6-character password using pwgen
password=$(pwgen -sBv1 6 1)

# Encrypt the password before storing it
encrypted_password=$(encrypt_password “$password“ “$PASSWORD_ENCRYPTION_KEY“)

# Store the encrypted password in the file
echo “$user:$encrypted_password“ >> “$PASSWORD_FILE“

# Create the user with the generated password
sudo useradd -m -p $(openssl passwd -6 “$password“) “$user“

# Set Bash as the default shell
set_bash_default_shell “$user“

# loop over each group in the groups array
for group in “${groupsArray[@]}“; do
group=$(echo “$group“ | xargs)

# Check if group exists, if not, create it
if ! grep -q “^$group:” /etc/group; then
sudo groupadd “$group“
echo “Created group $group“
fi

# Add user to the group
sudo usermod -aG “$group“ “$user“
echo “Added $user to $group“
done

# remove the created password from the current shell session
unset password