Automatic create continuous user.

add_user.sh

#!/bin/bash
if [ $(id -u) -eq 0 ]; then
	# as root user
	read -p "Username prefix: " username
	read -p "Password: " password
	read -p "Group: " group
	read -p "Quantity:" quantity
	read -p "Shell: " login
	grep -E "^$group" /etc/group > /dev/null
	if [ $? -ne 0 ]; then
		groupadd $group
		echo "Group $group created."
	fi
	pass=$(perl -e 'print crypt($ARGV[0], "password")' $password)
	current=0
	while [ $current -le "$quantity" ]
	do
		grep -E "^$username$current" /etc/passwd > /dev/null
		if [ $? -eq 0 ]; then
			echo "User $username$current is exists (Passed)"
			current=$(($current+1))
			continue
		fi
		useradd -m -s $login -p $pass -g $group $username$current
		echo "User $username$current has been created."
		current=$(($current+1))
	done
	[ $? -eq 0 ] && echo "All usr has been created!" || echo "Failed"
else
	echo "Only allow root user to add user!"
fi