Question

Problem 1
Write a BASH script to create a user account from the Linux system on which your script is run. The script should process two positional parameters.

• First positional parameter is supposed to be a string with a user name (e.g., user_name)
• Second positional parameter is supposed to be a string with a user password (e.g., user_password)

In your script:

• Check if two positional parameters were passed to your script when it was invoked
  • If NOT, print an appropriate message and terminate your script with error (i.e., use exit 1)
  • If YES, continue processing both positional parameters
• Create a new user on the Linux computer/system your script is run (you may have to run your script with root privileges or using sudo command to do it)
  • User’s account should have name denoted by the first positional parameter (e.g., user_name)
  • User’s account should have password denoted by the second positional parameter (e.g., user_password)
• Check if a new directory (e.g., user_name) was crated for the user under /home/ directory
  • If NOT, print an appropriate message and terminate your script with error
  • If YES, continue to the next step
• Check if the new user was added to the list of the users by checking /etc/passwd file (use grep command with user_name and find out if the line in it for the user was created)
  • If NOT, print an appropriate message and terminate your script with error
  • If YES, print an appropriate message that the user was successfully added and terminate your script with success (i.e., use exit 0)

Problem 2
Write a BASH script to delete a user account from the Linux system on which your script is run. The script should process one positional parameter.

• The positional parameter is supposed to be a string with a user name (e.g., user_name)

In your script:

• Check if a positional parameter was passed to your script when it was invoked
  • If NOT, print an appropriate message and terminate your script with error (i.e., use exit 1)
  • If YES, continue processing both positional parameters
• Check if a user account for the user name that was passed to your scrip as a positional parameter has an account on the Linux computer/system your script is run by checking /etc/passwd file (use grep command with user_name and find out if the line in it for the user was created)
  • If NOT, print an appropriate message and terminate your script with error (i.e., use exit 1)
  • If YES, continue processing both positional parameters
• Delete the user whose name was passed to your script as a positional parameter (e.g., user_name) from the Linux computer/system on which your script runs (you may have to run your script with root privileges or using sudocommand to do it)
• Check if a user’s directory (e.g., user_name) was deleted by checking if it still is under /home/ directory
  • If YES, print an appropriate message and terminate your script with error
  • If NOT, continue to the next step
• Check if a user’s account (e.g., user_name) was removed from the /etc/passwd file (use grep command with user_name and find out if the line in it for the user was created)
  • If YES, print an appropriate message and terminate your script with error
  • If NOT, print an appropriate message that the user was successfully removed and terminate your script with success (i.e., use exit 0)

Answer 1

#!/bin/bash

user_name=$1
user_password=$2

if [ -z "$user_name" ] || [ -z "$user_password" ]
then
   echo "usage: sudo bash adduser.sh <username> <password>"
   exit 1

elif [ $(id -u) -eq 0 ]; then
   egrep "^$user_name" /etc/passwd >/dev/null
   if [ $? -eq 0 ]; then
       echo "$user_name exists!"
       exit 1
   else
       pass=$(perl -e 'print crypt($ARGV[0], "password")' $user_password)
       useradd -m -p $pass $user_name
       [ $? -eq 0 ] && echo "User has been added to system!" || echo "Failed to add a user!"
   fi
else
   echo "Only root may add a user to the system"
   exit 2
fi

homedir=$(getent passwd "$USER" | cut -d: -f6)
if [ $homedir != "/home/"$user_name ]
then
   echo "Home directory exists"
   exit 3
else
   grep $user_name /etc/passwd
fi

Let me know if its working for you so i create part 2 for account deletion script. thanks