#!/bin/ksh
# This script adds a user to the file users.ref.  
# The correct syntax is "add userid fname lname'
# The variable error is used to detect errors.

error=n

# Detect the file users.ref - display error if not found.
if [[ ! -a users.ref && "$error" == "n" ]]
then echo "Unable to find users.ref file.  Try creating a link using 'ln'."
     echo "User information NOT added."
     error=y
fi

# Display error if current login doesn't have write permission for users.ref.
if [[ ! -w users.ref && "$error" == "n" ]]
then echo "You do not have write permission for users.ref.  Try chmod."
     echo "User information NOT added."
     error=y
fi

# Display correct syntax if no arguments are entered.
if [[ ! -n "$1" && "$error" == "n"]]
then echo "No arguments.  The correct syntax is 'add userid firstname lastname'."  
     echo "User information NOT added."
     error=y
fi

# Display error and correct syntax if too few arguments are entered.
if [[ ! -n "$3" && "$error" == "n"]]
then echo "Not enough information.  Please enter a userid, a first name, and a last name."
     echo "Ex: 'add dj1234 John Doe'"
     echo "User information NOT added."
     error=y
fi

# Display error if the new user already exists.  
if [ "$error" == "n"]
then grep $1 users.ref > exists.tmp
	if [ $? -eq 0 ]
	then echo "User id already exists in"
	     cat exists.tmp
	     echo "User information NOT added."
	     rm exists.tmp
	     exit 1
	     error=y
	fi
fi

# Detect previous errors.  If none, then add user info.
if [ "$error" == "n" ]
then echo $1 $2 $3 >> users.ref
     echo "You added $1 $2 $3 to users.ref.  If this is incorrect, please use the remove utility."
fi