The Linux Newbie Guide - usermod Command

The Linux Newbie Guide

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Fundamentals

usermod - Modify User Accounts

The usermod command is used to modify user accounts on a Unix-like operating system. It can only be executed by the superuser (root) as it involves making changes to system user account information. usermod is a versatile command that allows you to change various aspects of a user account.

The basic syntax for the usermod command is as follows:
usermod [OPTIONS] USERNAME 。

Here, "USERNAME" is the name of the user account you want to modify.

Some of the commonly used options for the usermod command include:

-d : Specify the user account's home directory.
-g : Specify the user account's primary group.
-G : Specify additional groups for the user account.
-s : Specify the user account's default shell.
-u : Specify the user account's UID (User ID).
-L : Lock the user account, preventing login.
-U : Unlock the user account, allowing login.

For example, if you're logged in as the root user and want to change a user's primary group:

# usermod -g sales hr ←Change the primary group of user "hr" to "sales"

Please note that you should exercise caution when making changes to user accounts, especially when altering their UID or locking/unlocking accounts.

For more detailed explanations and additional examples of the usermod command, you can refer to the provided link.