responding to a double password prompt with Fabric

BrainLikeADullPencil asked:

I’m using this Fabric function to try to add a user to a Ubuntu server. It’s not throwing an error, but I can’t login with the user that I’m trying to add after the script’s finished. If I add a user manually, after I run the adduser myusername command, I get prompted twice to enter a password. In this script, the repeated prompt (as I call it) is being dealt with (uneffectively, I believe) by passing the password twice to this echo command

 if not sudo("adduser %s | echo -e '%sn%sn'" % (new_user,passwd,passwd)).failed:

Can you explain how that would more appropriately be dealt with in this function?

def user_add(new_user, passwd=False):
    """Add new user"""
    with settings(hide('running', 'stdout', 'stderr'), warn_only=True):
        # if is_host_up(
        if not passwd:
                passwd = generate_passwd()
            if not sudo("adduser %s | echo -e '%sn%sn'" % (new_user,passwd,passwd)).failed:
                run('echo "{user} ALL=(ALL:ALL) ALL" >> /etc/sudoers'.format(user=new_user))
                ...other code not included

My answer:

adduser is just a Debian/Ubuntu-specific front-end to the more normal useradd command, which takes a variety of options on the command line, including a pre-hashed password as its -p option. For this you should probably be calling useradd with the desired options instead of adduser.

On most other Linux distributions, adduser is simply symlinked to useradd, or absent entirely.

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