Shell Programming and Scripting

echo "${passwd}" | awk '/[a-z]/ && /[A-Z]/ && /[0-9]/ && /\W/ && (length($0) >=8 ) && (length($0) <= 16 ) { X=1 } END { exit(!X) }'

#!/bin/bash
# scriptname: create_new_user
# purpose: to create a new user

# functionname: loginname_validation
# purpose: to validate the loginname which is used to add a new user
function loginname_validation()
{
	local loginname="${1}"
	if grep -q "^${loginname}:" /etc/passwd && echo "The loginname already exists." 
	then
		return 1
	elif [ -z "${loginname}" ] && echo "You should enter a nonempty loginname." 
	then
		return 1
	elif echo "${loginname}" | grep -q '^[_a-Z][0-9a-Z_@.-]\{6,16\}[_a-Z0-9]$' && echo "You have entered a valid loginname." 
	then
		return 0 
	else
		echo "The loginname must start and end with a underscore or an alphabet. And its length must be between 8 and 16 characters long. Only alphabet or digit or 4 kinds of punctuation(@_-.) is allowable."
		return 1
	fi
}

# functionname: password_validation
# purpose: to validate the password
function password_validation()
{
	local passwd="${1}"
	if [ -z "${passwd}" ] && echo "The password must not be empty." 
	then
		return 1
	elif echo "${passwd}" | awk '/[a-z]/ && /[A-Z]/ && /[0-9]/ && /\W/ && (length($0) >=8 ) && (length($0) <= 16 ) { X=1 } END { exit(!X) }' && echo "You have entered a valid password."
	then
		return 0 
	else
		echo "The password must contain at least one lowercase and one uppercase and one digit and one punctuation, and its length must be between 8 and 16 characters long."
		return 1
	fi
}

# functionname: uid_validation
# purpose: to validate the uid
function uid_validation()
{
	local uid="${1}"
	if [ x"${uid}" = x`awk -F: '{print $3}' /etc/passwd | grep "^${uid}$"` ] && echo "The UID already exists."
	then
		return 1
	elif echo ${uid} | awk '/^[0-9][0-9]*[0-9]$/ && (($0) >= 500) && (($0) <= 32767) { X=1 } END { exit(!X) }' && echo " The UID is valid."
	then
		return 0
	else
		echo "You should enter a number between  500 and 32767 as UID."
		return 1
	fi
}

# functionname: grpname_validation
# purpose: to validate the groupname
function grpname_validation()
{
	local grpname="${1}"
	if grep -q "^${grpname}:" /etc/group && echo "The groupname already exists." 
	then
		return 1
	elif [ -z "${grpname}" ] && echo "You should enter a nonempty groupname." 
	then
		return 1
	elif echo "${grpname}" | grep -q '^[_a-Z][0-9a-Z_@.-]\{6,16\}[_a-Z]$' && echo "You have entered a valid groupname." 
	then
		return 0 
	else
		echo "The groupname must start and end with a underscore or an alphabet. And its length must be between 8 and 16 characters long. Only alphabet or digit or 4 kinds of punctuation(@_-.) is allowable."
		return 1
	fi
}

# functionname: fullname_validation
# purpose: to validate the fullname
function fullname_validation()
{
	local fullname="${1}"
	if [ -z "${fullname}" ] && echo "You should enter a nonempty fullname." 
	then
		return 1
	elif echo "${fullname}" | grep -q '^[a-Z][a-Z. -]\{4,16\}[a-Z]$' && echo "You have entered a valid groupname." 
	then
		return 0 
	else
		echo "The fullname must start and end with an alphabet. And its length must be between 8 and 16 characters long. Only alphabet or 2 kinds of punctuation(-.) is allowable."
		return 1
	fi
}

# functionname: homedir_validation
# purpose: to validate the homedir
function homedir_validation()
{
	local homedir="${1}"
	if [ -z "${homedir}" ] && echo "You should enter a nonempty home directory." 
	then
		return 1
	elif echo "${homedir}" | grep -E -q '^\/([0-9a-Z_.-]+\/?)+$' && echo "You have entered a valid home directory." 
	then
		return 0
	else
		echo "The absolute path of home directory shouldn't contain metacharacters."
		return 1
	fi
}

# functionname: add_newuser
# purpose: to add a new user
function add_new_user()
{
# enter a login name
read -p "Please enter a new loginname: " ln
until loginname_validation $ln
do
	read -p "Please enter a new loginname: " ln
done

# enter a password
while true
do
	read -p "Please enter your password: " pw
	until password_validation $pw
	do
		read -p "Please enter your password: " pw
	done
	read -p "Please confirm your password: " confirmpw
	if [ $confirmpw == $pw ]
	then
		break
	else
		echo "The passwords do not match.Please reenter."
		continue 1
	fi
done
encrypted_pw=`openssl passwd -crypt $confirmpw`

# enter a user id
read -p "Specify a UID Automatically? (Y/N)" isautomatic
case $isautomatic in
Y|y)
#	uidopt=""
;;
*)
	read -p "Please enter a UID: " uid
	until uid_validation $uid
	do
		read -p "Please enter a UID: " uid
	done
	uidopt="-u $uid"
;;
esac

# choose a group

read -p "Create a Group Automatically? (Y/N)" isautomatic
case $isautomatic in
Y|y)
	grpname="$ln"
#	grpopt=""
;;
*)
	read -p "Use an existing group? (Y/N)" issetgroup
	case $issetgroup in
	Y|y)
		read -p "Enter the groupname: " grpname
		until grep -q "^${grpname}:" /etc/group
			do
				echo "Specified group not found."
				read -p "Enter the groupname: " grpname
			done
	;;
	*)
		read -p "Enter the new groupname: " grpname
		until grpname_validation "$grpname"
		do
			read -p "Enter the new groupname: " grpname
		done
		groupadd $grpname
	;;
	esac
	grpopt="-g $grpname"
;;
esac

# enter a fullname

read -p "Use the loginname as the full name? (Y/N)" isautomatic
case $isautomatic in
Y|y)
	fullname="$ln"
;;
*)
	read -p "Please enter the FullName: " fullname
	until fullname_validation "$fullname"
	do
		read -p "Please enter the FullName: " fullname
	done
;;
esac
# enter the home directory

read -p "Create Home Directory Automatically? (Y/N)" isautomatic
case $isautomatic in
Y|y)
	homedir="/home/$ln"
	homediropt="-m"
;;
*)
	read -p "Use an existing directory as the Home Directory? (Y/N)" issethomedir
	case $issethomedir in
	Y|y)
		read -p "Enter the absolute path of the specified directory: " homedir
		until [ -d "$homedir" ]
			do
				echo "Specified directory not found."
				read -p "Enter the absolute path of the specified directory: " homedir
			done
	;;
	*)
		read -p "Enter the absolute path of the Home Directory you want: " homedir
		until homedir_validation "$homedir"
		do
			read -p "Enter the absolute path of the Home Directory you want: " homedir
		done
	;;
	esac
	homediropt="-m -d $homedir"
;;
esac
# enter the login shell

read -p "Choose the /bin/bash as login shell? (Y/N)" isautomatic
case $isautomatic in
Y|y)
	loginshell="/bin/bash"
#	lsopt=""
;;
*)
	read -p "Please enter the login shell: " loginshell
	until grep -q "$loginshell" /etc/shells
	do
		echo "Not invalid loginshell."
		read -p "Please enter the login shell: " loginshell
	done
	lsopt="-s $loginshell"
;;
esac

# add the new user
echo "The info of new user is shown below:"
printf "%-16s %-16s\n" "Login Name:" "$ln"
printf "%-16s %-16s\n" "Password:" "$confirmpw"
printf "%-16s %-16s\n" "Group Name:" "$grpname"
printf "%-16s %-16s\n" "Full Name:" "$fullname"
printf "%-16s %-16s\n" "Home Directory:" "$homedir"
printf "%-16s %-16s\n" "Login Shell:" "$loginshell"
read -p "Ready to create? (Y/N)" isreallycreate
case $isreallycreate in
Y|y)
	useradd -p "${encrypted_pw}" $uidopt $grpopt -c "$fullname" $homediropt $lsopt "$ln"
;;
*)
	echo "Canceled."
esac
}

add_new_user
:<<COMMENT
# change the permission, ownership and group of home directory
echo "Start to change the permission of $homedir. You have three options: "
echo "1) Give all permissions to the owner, give read and execute permissions to everyone else."
echo "2) Give read and write permissions to the owner and group, give read permissions to others."
echo "3) Ohter."
read -p "Enter the number you choose: " option
case $option in
1)
	chmod -R 755 $homedir
;;
2)
	chmod -R 644 $homedir
;;
*)
	read -p "Enter 3 permission bits you want: " coption
	until echo "$coption" | grep -q '^[0-7][0-7][0-7]$'
	do
		echo "You should enter 3 permission bits each of which is 0-7."
		read -p "Enter 3 permission bits you want: " coption
	done
	chmod -R "$coption" $homedir
;;
esac
chown -R "$loginname:$grpname" $homedir
COMMENT

stty -echo
print -n Enter password: 
stty echo