useradd

Additional Notes

useradd creates a local user account. It can set a home directory, login shell, UID, primary group, supplementary groups, and account metadata.

On Debian and Ubuntu systems, adduser is often friendlier for interactive account creation, while useradd is lower-level and script-friendly.

Syntax

useradd [options] username

Parameters

• options: Flags that change how useradd behaves.
• user: User account affected by the command.
• group: Group account affected by the command.
• file: File or directory whose ownership, mode, or access policy is being changed.

Common Options

• -m, --create-home: Create the user's home directory.
• -d DIR, --home-dir DIR: Set home directory path.
• -s SHELL, --shell SHELL: Set login shell.
• -g GROUP: Set primary group.
• -G GROUPS: Set supplementary groups.
• -u UID: Set numeric user ID.
• -c COMMENT: Set comment/GECOS field.
• -r, --system: Create a system account.
• -M: Do not create a home directory.

Examples

sudo useradd -m deploy

Create user deploy with a home directory.

sudo useradd -m -s /bin/bash alice

Create alice with Bash as login shell.

sudo useradd -m -G sudo,docker alice

Create alice and add supplementary groups.

sudo passwd alice

Set the new user's password.

id alice

Check the new account identity and groups.

Practical Notes

• Always set or configure authentication after creating a login account.
• Use -m unless you intentionally do not want a home directory.
• Supplementary group changes apply on new login sessions.
• Service accounts often use -r and a non-login shell.
• Review /etc/passwd, /etc/shadow, and /etc/group only if you understand their format.