Useradd command takes single login input by default. You can use for loop like this..
for USER in user1 user2 user3 user4 user5 do useradd -m $USER done
This will create the users with default shell, default group. If you want specific shell, specific group or specific command, you can pass the informations to the useradd command.
> plz let me know any option with useradd command to create multiple users at a time, without using script.
Define "script". If I write more than one command on the command line is that considered a script or not? If the multiple commands and operators don't easily fit in (for example) an 80-character command line and I then put them into a file for repeated use and/or maintainability, that's generally called a "script".
Why are you so concerned here?
With regard to 'useradd' the anwser to your question is "no".
