Linux shell script สำหรับ add user ทีละหลายๆ user

#!/bin/bash
# Script to add a user to Linux system

for ((  i = 1 ;  i <= 50;  i++  ))
do

if [ $(id -u) -eq 0 ]; then
 egrep "^user$i" /etc/passwd >/dev/null
 if [ $? -eq 0 ]; then
  echo "$username exists!"
  exit 1
 else
  pass=$(perl -e 'print crypt($ARGV[0], "password")' "123456")
  useradd -m -p $pass user$i
  [ $? -eq 0 ] && echo "user$i has been added to system!" || echo "Failed to add a user!"
 fi
else
 echo "Only root may add a user to the system"
 exit 2
fi

done