Create Linux User

The Problem

You need a new user account on your server — for a team member, a specific application, or to stop using root directly — but getting the permissions, home directory and shell access right takes a bit more than a single command.

About this problem

Creating a Linux user is simple on the surface, but getting it right for a specific purpose (an application service account that shouldn't have a login shell, versus a team member who needs sudo and SSH key access) involves several small decisions that are easy to get wrong if you're not used to it.

This comes up whenever a new person joins a project, or when setting up a dedicated account for a specific application or service to run under, rather than root.

What's Included

• Creating the user account with an appropriate home directory and shell
• Setting up sudo access if the account needs administrative privileges
• Configuring SSH key-based access for the new user
• Setting correct group memberships for anything the account needs to access

What's NOT Included

• Setting up the actual application or service the account will run (separate service)
• Ongoing user account management after initial creation
• Password policy/complexity enforcement beyond a reasonable initial setup

How It Works

1. Create the user account with useradd (or adduser) specifying an appropriate home directory and shell.
2. Add the user to the sudo group if administrative access is required, or deliberately leave it out for a restricted service account.
3. Set up the user's SSH authorized_keys for key-based login rather than a password.
4. Add the user to any additional groups needed for specific file or service access (e.g. docker, www-data).
5. Test login and, if applicable, sudo access to confirm everything works as intended.

In practice: you buy the service, send over whatever access or details the job needs, I investigate and do the work, and you confirm it's resolved before we call it done.

Frequently Asked Questions

What's the difference between useradd and adduser?

useradd is a lower-level command with fewer defaults set automatically; adduser (available on Debian/Ubuntu) is a friendlier script that sets up a home directory and prompts for details automatically.

Should a new user have sudo access?

Only if they genuinely need administrative privileges — accounts meant only for running a specific application are usually best left without sudo, limiting the damage if that account is ever compromised.

Can I create a user without a login shell?

Yes, setting the shell to /usr/sbin/nologin or /bin/false is standard for service accounts that should never be used for interactive login.

How do I give a new user SSH key access instead of a password?

By placing their public key in ~/.ssh/authorized_keys under their home directory with the correct permissions, then optionally disabling password authentication entirely.

What groups does a new user need to access a website's files?

Typically the group that owns the web root (often www-data or similar), so the user can read/write files without needing broader permissions.

How do I remove a user account later?

userdel (with the -r flag to also remove their home directory) cleanly removes the account, though it's worth checking for any files or cron jobs owned by that user first.