Home / ubuntu / Questions / 94060
Accepted
Lorin Hochstein
Asked: 2012-01-10 05:54:52 +0800 CST

Run adduser non-interactively

  • 772

I'd like to use the adduser command to add a user (with disabled password) via a shell script.

By default, adduser prompts you for various values (e.g., Full Name). Is there any way to submit these values via command line? Or will I need to useradd instead?

adduser

3 Answers

  1. Best Answer

    Use the --gecos option to skip the chfn interactive part.

    adduser --disabled-password --gecos "" username

    It's all in the man page. Not the most obvious formulation tho.

    --gecos GECOS
          Set  the  gecos field for the new entry generated.  adduser will
          not ask for finger information if this option is given.

    The GECOS field is a comma separated list as such: Full name,Room number,Work phone,Home phone, despite that man page mentions finger information Details - Wikipedia

    Hope this helps you.

    • 386

  2. useradd can also add users and does not appear to have any form of prompting built in.

    useradd -m -p <encryptedPassword> -s /bin/bash <user>
    • -m, --create-home: Create user home directory
    • -p, --password: Specify user password; skip to have it disabled

    • -s, --shell: Default shell for logon user

      Blank will use default login shell specified by the SHELL variable in /etc/default/useradd

    • Substitute <user> with the login name
    • Substitute <encryptedPassword> with the encrypted password

    Generating a hashed password:

    There are a lot of crypt3 implementations that can generate a hashed password. The whole thing is your hashed password.

    Sha-512 Based

    The resulting output format: the hash mechanism ($6 for sha-512), the random salt (the eight bytes after the second dollar sign $ASDF1234), remainder is the payload.

    • mkpasswd mkpasswd -m sha-512

      (mkpasswd is provided by the whois package)

    DES based:

    The resulting output format: first 2 bytes is your salt, remainder is the payload. The whole thing is your hashed password.

    • mkpasswd: mkpasswd (provided by whois package)
    • openssl: openssl passwd -crypt
    • perl: perl -e "print crypt('password');"
    • python: python3 -c 'import crypt; print(crypt.crypt("password"))'
    • 66

  3. You can combine what @ThorSummoner @Zoke are saying like so:

    username=jovyan
password=jovyan

adduser --gecos "" --disabled-password $username
chpasswd <<<"$username:$password"

    I'm doing this for my Jupyter docker-stack. It allows full headless setup in a Dockerfile.

    • 14