Add A User to Linux Shell Script
The following code is a Linux Shell Script that is menu based to add or remove users. You could always use the GUI but real men don’t. This was created for Redhat. WordPress unfortunatley affects the formatting a bit, the script is available to download below.
#!/bin/bash# User Add Menu #2 by Aaron Rockey - October 2009
clear # Clears the screen.
echo "Adding or Removing Users Menu"
echo "*****************************"
echo "Choose from an option below:"
echo
echo "[1]add user simple method"
echo "[2]add user with full name"
echo "[3]add user with different shell"
echo "[4]view last 5 users added to system"
echo "[5]remove a user"
echo "[6]remove a user and their home dir"
echo "[7]Exit"
read option
while [ "$option" -ne "7" ]
do
case "$option" in
# Note variable is quoted.
"1")
if [ $(id -u) -eq 0 ]; then
#If UserID is root then procede if not then proceeds to else statement
read -p "Enter username : " username #get input
read -p "Enter password : " password #get input
grep "^$username" /etc/passwd >/dev/null
#Search /etc/passwd for name, ouput result to null
if [ $? -eq 0 ]; then
echo "$username already exists!" #Display error message if name exists
else
pass=$(perl -e 'print crypt($ARGV[0], "password")' $password)
#encrypt password
useradd -p $pass $username #add user name and password to system
if [ $? -eq 0 ] ; then #if no errors output message
echo "User $username has been added to system"
#Display positive message
else
echo "Failed to add user $username" #Display negative message
fi
fi
else
echo "Only root may add a user to the system"
#Output if user was not root executing script
fi
;;
"2")
if [ $(id -u) -eq 0 ]; then
#If UserID is root then procede if not then proceeds to else statement
read -p "Enter username : " username #get input
read -p "Enter password : " password #get input
read -p "Enter fullname : " fullname #get input
grep "^$username" /etc/passwd >/dev/null
#Search /etc/passwd for name, ouput result to null
if [ $? -eq 0 ]; then
echo "$username already exists!" #Display error message if name exists
else
pass=$(perl -e 'print crypt($ARGV[0], "password")' $password)
#encrypt password
useradd -p $pass $username #add user name and password to system
usermod -c "$fullname" $username #adds users full name
if [ $? -eq 0 ] ; then #if no errors output message
echo "User $username has been added to system" #Display positive message
else
echo "Failed to add user $username" #Display negative message
fi
fi
else
echo "Only root may add a user to the system"
#Output if user was not root executing script
fi
;;
"3")
if [ $(id -u) -ne 0 ]; then
#If UserID is root then procede if not then output error message
echo "Only root may add a user to the system"
#Output if user was not root executing script
else
read -p "Enter username : " username #get input
read -p "Enter password : " password #get input
read -p "Enter login shell eg: /bin/ksh:" shell #get input
grep "^$username" /etc/passwd >/dev/null
#Search /etc/passwd for name, ouput result to null
if [ $? -eq 0 ]; then
echo "$username already exists!" #Display error message if name exists
else
grep "^$shell" /etc/shells >/dev/null
#Search /etc/shells for existing shell types, ouput result to null
if [ $? -ne 0 ]; then
echo "$shell is an invalid shell!"
else
pass=$(perl -e 'print crypt($ARGV[0], "password")' $password)
#encrypt password
useradd -p $pass -s $shell $username
#add user to system and change default shell
if [ $? -eq 0 ] ; then #if no errors output message
echo "User $username has been added to system" #Display positive message
else
echo "Failed to add user $username" #Display negative message
fi
fi
fi
fi
;;
"4")
if [ $(id -u) -eq 0 ]; then
#If UserID is root then procede if not then proceed to else statement
tail -5 /etc/passwd
else
echo "Only root may perform this command"
#Output if user was not root executing script
fi
;;
"5")
if [ $(id -u) -eq 0 ]; then
#If UserID is root then procede if not then proceeds to else statement
read -p "Enter username to remove: " username #get input
grep "^$username" /etc/passwd >/dev/null
#Search /etc/passwd for name, ouput result to null
if [ $? -ne 0 ]; then
echo "$username does not exist!" #Display error if username not in /etc/passwd
else
userdel $username #remove user from the system
if [ $? -eq 0 ] ; then #if no errors output message
echo "User $username has been removed from the system"
#Display positive message
else
echo "Failed to remove user $username" #Display negative message
fi
fi
else
echo "Only root may remove a user"
#Output if user was not root executing script
fi
;;
"6")
if [ $(id -u) -eq 0 ]; then
#If UserID is root then procede if not then proceeds to else statement
read -p "Enter username to remove: " username #get input
grep "^$username" /etc/passwd >/dev/null
#Search /etc/passwd for name, ouput result to null
if [ $? -ne 0 ]; then
echo "$username does not exist!" #Display error if username not in /etc/passwd
else
userdel -r $username #remove user and home dir from the system
if [ $? -eq 0 ] ; then #if no errors output message
echo "User $username and their home dir has been removed from the system"
#Display positive message
else
echo "Failed to remove user $username" #Display negative message
fi
fi
else
echo "Only root may remove a user"
#Output if user was not root executing script
fi
;;
"7")
#Option 7 Exit was entered script ending
;;
* ) #Executes this if the user enters an invalid menu number
echo "Invalid choice! Options are..."
;;
esac
echo
echo "[1]add user simple method"
echo "[2]add user with full name"
echo "[3]add user with different shell"
echo "[4]view last 5 users added"
echo "[5]remove a user"
echo "[6]remove a user and their home dir"
echo "[7]Exit"
echo "Enter your choice: "
read option
done Aaron
