Add a new user to Amazon EC2 instance

After connecting to your Amazon EC2 instance, you can add a new user with sudo privilege with following steps:

1. Open a putty session, log in with the default user, ec2-user
2. sudo su
3. useradd new_user_name
4. passwd new_user_name, give a password for the new user
5. vim /etc/sudoers, insert line "new_user_name ALL = NOPASSWD: ALL" at the end of the file
6. cd /home/new_user_name
7. mkdir .ssh
8. cp ../ec2-user/.ssh/authorized_keys .ssh/authorized_keys
9. chown -R new_user_name:new_user_name .ssh
10. chmod 700 .ssh
11. chmod 600 .ssh/*

Open another putty session and log in with the same private key you use for ec2-user.