CLI:Basics – User Management in Linux

Welcome back to the CLI:Basics series! In this post, we’ll cover essential user management commands for Linux. Even if you’re the only user on your system, it’s important to understand how user accounts and groups work—because on Linux, you are the system administrator.

Whether you’re managing one account or one million (okay, probably not literally), these concepts scale the same.

We’ll walk through:

• Checking your user and group info
• Adding and removing users
• Assigning users to groups
• Setting user passwords

Let’s get started.

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👤 id – Display User and Group Info

id

This shows:

• Your user ID (UID)
• Your group ID (GID)
• A list of groups you belong to

Example output:

uid=1000(ltl) gid=1000(ltl) groups=1000(ltl),4(adm),27(sudo),...

• UIDs below 1000 are typically system accounts.
• UIDs 1000+ are normal user accounts (you, your roommate, etc).

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❓ whoami – Who Am I Really?

whoami

This command returns the current effective user, which is especially helpful after using sudo:

sudo -i
whoami

Output:

root

Even though you’re logged in as yourself, you’re now operating as root.

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👥 groups – Show Group Membership

groups

Lists all groups your current user belongs to. This includes standard groups like users, sudo, lpadmin, etc. Being in sudo allows you to run commands with elevated privileges.

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➕ useradd – Create a New User

sudo useradd -m scott

The -m flag ensures the user’s home directory is created at /home/scott. Without sudo, this command will fail due to insufficient permissions.

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🔑 passwd – Set a User’s Password

sudo passwd scott

After creating a user, use this to assign them a login password.

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➖ userdel – Remove a User Account

sudo userdel scott

This removes the system-level account and login access, but does not delete their home directory by default. That means /home/scott will remain, which is useful if you need to access their files later.

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🛠️ usermod – Modify User Groups

sudo usermod -aG sudo scott

This command:

• -aG appends the user to one or more groups (in this case, sudo)
• Gives Scott permission to run commands as root using sudo

⚠️ Be careful not to overwrite existing group memberships when using usermod without -a.

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Notes on Teaching Order

You may notice some “out of order” teaching in these videos—and that’s intentional. Many commands build on each other, and it’s hard to introduce one without touching another. The goal is to keep things realistic and practical, not just academically tidy.

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Summary of Commands Covered

Command	Description
id	Show user ID, group ID, and memberships
whoami	Show current effective user
groups	Show current user’s group memberships
useradd -m	Add a new user with a home directory
passwd	Set or update a user’s password
userdel	Remove a user account
usermod -aG	Add a user to a group

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Final Thoughts

User management is a fundamental skill for any Linux user—even if you’re the only person using the system. As we move further into this series, we’ll begin touching on multi-user environments, permissions, and access control.

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