What is the difference between adduser and useradd on Ubuntu?

adduser is a high-level Perl front-end specific to Debian and Ubuntu. It creates the home directory, copies the /etc/skel files, creates a matching group and prompts for a password. useradd is the low-level binary present on every Linux distribution; it creates only the account entry unless you pass flags such as -m for the home directory. Use adduser for human accounts and useradd in portable scripts.

Why does adduser print no output on Ubuntu 26.04?

Ubuntu 26.04 ships adduser 3.153, which defaults to STDOUTMSGLEVEL=warn in /etc/adduser.conf. The familiar 'Adding user' and 'Creating home directory' lines are info-level messages, so they are suppressed. Run adduser with --stdoutmsglevel=info to get the old output back, or check /var/log/auth.log where LOGMSGLEVEL still defaults to info.

How do I give a user sudo access on Ubuntu Server?

Run sudo usermod -aG sudo username. The -a flag appends and -G names the group; omitting -a would replace all of the user's secondary groups. Confirm with groups username and check the effective rules with sudo -l -U username. The user must log out and back in before the new group takes effect.

Why does my sudo prompt say '[sudo: authenticate] Password:' instead of '[sudo] password for user:'?

Ubuntu 26.04 replaced the original C sudo with sudo-rs, a memory-safe Rust reimplementation. It uses different prompt wording, echoes asterisks as you type, and reports 'interactive authentication is required' where classic sudo said 'a password is required'. The commands and sudoers syntax are unchanged.

How do I delete a user on Ubuntu Server?

Run sudo deluser username to remove the account while keeping its home directory, or sudo deluser --remove-home username to delete the home directory too. Kill the user's running processes first with sudo pkill -u username, and consider sudo deluser username sudo to revoke only administrative rights instead of removing the account.

Do I need to set a password if the user logs in with an SSH key?

Yes, if the account uses sudo. SSH keys authenticate the login, but sudo asks for the account's own Unix password. An account with no password set cannot authenticate to sudo at all. For non-interactive automation accounts, configure a NOPASSWD rule in /etc/sudoers.d instead of leaving the password blank.

2 posts tagged with "Command Line Interface"

Command Line Interface Tools and Techniques

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Build a Command-Line Text Analyzer in Python - Step by Step

July 20, 2025 · 7 min read

Jagdish Kumawat

Founder @ Dewiride

Build a Command-Line Text Analyzer in Python that reads a text file, counts lines or words, displays frequent words, detect long lines.

How to Create a New User in Linux Ubuntu Server with Sudo and SSH Access

June 28, 2025 · 30 min read

Jagdish Kumawat

Founder @ Dewiride

Learn how to create a new user in Linux Ubuntu Server, grant it sudo administrator rights, set up SSH key login, add it to groups, and control password expiry — with every command run on a real Ubuntu 26.04 LTS server and the actual output shown.

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