Day-04 shell scripting
1. Now we can check the username and if the users don’t exit then create the user.
2. Now we can create random password with special characters.
3. Now we can Force the user to reset the password during first time login.
### step: We can check the valid parameters are passed or not by using the below script
#!/bin/bash
if [ $# -gt 0 ]; then
USER=$1
echo $USER
else
echo “Please enter a valid parameter”
fi
### We need to find the how many user are there in VM by using the below script
### There is a particular path to find the user already there or not in machine.
cat /etc/passwd
### Now i need to find the user is there or not with user name with the help of below grep command
cat /etc/passwd | grep -i -w Ubuntu1
##Now i want take the 1st part of the output to display the user name in output by using the below command
cut -d “:” -f1
cat /etc/passwd | grep -i -w Ubuntu1 | cut -d “:” -f1
### Adding — User
#!/bin/bash
if [ $# -gt 0 ]; then
USER=$1
echo $USER
EXISTING_USER=$(cat /etc/passwd | grep -i -w $USER | cut -d “:” -f1)
if [ “$USER” = “$EXISTING_USER” ]; then
echo “The user $USER is already present on the machine. Please enter another username.”
else
echo “Let’s create a new user.”
sudo useradd -m $USER — shell /bin/bash
fi
else
echo “Please enter valid parameters.”
fi
##password ##
#Now we need to write a script for generating password
#!/bin/bash
### Check if a username is provided as an argument
if [ $# -gt 0 ]; then
USER=$1
echo $USER
EXISTING_USER=$(cat /etc/passwd | grep -i -w $USER | cut -d “:” -f1)
# Check if user already exists
if [ “${USER}” = “${EXISTING_USER}” ]; then
echo “The $USER you have entered is already present in the machine, Please Enter the Another USername”
else
echo “Creating new username: $USER”
sudo useradd -m $USER — shell /bin/bash
# Generate a random password with a special character
SPEC=$(echo ‘!@#$%^&*()_’ | fold -w1 | shuf | head -1)
PASSWORD=”P@ssw0rd${RANDOM}${SPEC}”
# Set the password for the new user
echo “$USER:$PASSWORD” | sudo chpasswd
echo “The temporary password for $USER is: ${PASSWORD}”
# Expire the password so the user has to change it on first login
passwd -e $USER
fi
else
echo “Please Enter the Valid parameter.”
fi
### Now we can use the sed stream editor to modify the sshd_config file, particularly changing the PasswordAuthentication.
sed -i “58 s/.*PasswordAuthentication.*/PasswordAuthentication yes/g” /etc/ssh/sshd_config
## Multi User passing
### Now we can passing the multiple user with the help of for loop and generating the random password with the help of special characters
### Check if any username is passed as an argument
if [ $# -gt 0 ]; then
for USER in “$@”; do
echo $USER
EXISTING_USER=$(cat /etc/passwd | grep -i -w $USER | cut -d “:” -f1)
# Check if the user already exists
if [ “${USER}” = “${EXISTING_USER}” ]; then
echo “The $USER you have entered is already present in the machine, Please Enter the Another USername”
else
echo “Lets Create a new Username”
sudo useradd -m “$USER” — shell /bin/bash
# Generate a random password with a special character
SPEC=$(echo ‘!@#$%^&*()_’ | fold -w1 | shuf | head -1)
PASSWORD=”P@ssw0rd${RANDOM}${SPEC}”
# Set the password for the new user
echo “$USER:$PASSWORD” | sudo chpasswd
# Check if the password was set successfully
if [ $? -eq 0 ]; then
echo “The temporary password for $USER is: $PASSWORD”
# Expire the password to force change at first login
passwd -e “$USER”
else
echo “Failed to set password for $USER.”
fi
fi
done
else
echo “Please Enter the Valid parameter.”
fi
