#!bin/bash

function check()
{


arg1=$1
arg1="'"$arg1"'"
arg2="/etc/$2"
arg3="^$3"
arg4=$4

commandLine="awk -F':' $arg1 $arg2 |grep $arg3 > $arg4"

eval $commandLine

return $?
}
function checkUserExists(){
 check 1 passwd $1 /dev/null
 return $?
}
function checkGroupExists(){
 check 1 group $1 /dev/null
 return $?
[user1@localhost ~]$ vi check.sh
[user1@localhost ~]$ more check.sh
#!bin/bash

function check()
{


arg1=$1
arg1="'"$arg1"'"
arg2="/etc/$2"
arg3="^$3"
arg4=$4

commandLine="awk -F':' $arg1 $arg2 |grep $arg3 > $arg4"

eval $commandLine

return $?
}
function checkUserExists(){
 check 1 passwd $1 /dev/null
 return $?
}
function checkGroupExists(){
 check 1 group $1 /dev/null
 return $?
}
function checkUIDExists(){
 check 3 passwd $1 /dev/null
 return $?
}
function checkGroupUIDExists(){
 check 3 group $1 /dev/null
 return $?
}

function usage(){
 echo "How to\n"
 echo "PARAMETERS : \n"
 echo "'-u' <user> : create user
 echo "'-ug' <user> <group> : create user and add it to the group"
 echo "Req : Launch the program as Administrator\n"
}

function main(){
 if [[ $EUID -ne 0 ]] ; then
   echo "You must run this program as root !"
   exit 1
 else
   if [ $# -ne 3 -o $# -ne 2 ] ; then
	echo "Error in the parameters"
        exit 1
   else
	case "$1" in
	-u) if [ $# -e 2 ] ; then
	      createUser $2
            else
	      echo "Error incorrect number of param for '-u' , need a username"
              exit 3
	    fi
            ;;
        -ug) echo "Not implemented yet"
              exit 4
            fi
            ;;
         *) echo "INVALID OPTION"
            exit 6
            ;;
         esac
   fi
fi
return 0
}

function createUser(){
	checkUserExists $1
        if [ $? -e 0 ]; then
           uid=$(awk -F":" 'END { print $3 }' /etc/passwd)
           uid=$((uid+1))

            if [ $uid -le 500 ]; then
                uid=501
            fi
	    checkUIDExists() $uid
            if [ $? -ne 0 ]; then
                checkGroupUIDExists $uid
            fi
            while [ $? = 0 ]; do
                uid=$((uid+1))
                checkUIDExists $uid
                if [ $? -ne 0 ]; then
                    checkGroupUIDExists $uid
                fi
            done

            echo "$1:x:$uid:$uid:$1:/home/$1:/bin/bash" >> /etc/passwd
            echo "$1:x:$uid:" >> /etc/group
            mkdir /home/$1
            cp -vR /etc/skel/.bash* /home/$1
            chmod -vR 0755 /home/$1
            chown -vR $1:$1 /home/$1
            passwd $1

}
main $1 $2 $3 $4