How to Check if Running as root in a BASH Script?

Hello, @ServerEnthusiast

The examples provided by @bobbyiliev and @KDSys should help you to check if the script is executed from the root username.

Something to keep in mind is not to use the whoami command in order to check if the script is executed from root. A root user does not have to be named “root”. whoami returns the first username with user ID 0. $USER contains the name of the logged in user, which can have user ID 0, but have a different name.

As per @KDSys example, you can use: id -un in order to be sure that the script is actually executed from the root username.

This is from the man page if id

-u, --user
print only the effective user ID

-n, --name
print a name instead of a number, for -ugG

Regards, Alex

Hi @ServerEnthusiast,

As @bobbyiliev said, there are a few ways to check that so here is my way.

What I find best when I’m writing in any language is to place variables whenever possible. If you are going to reuse the command, it’s better to have it in a variable.

Here is how I’ll usually do it, it’s more or less the same as above however with a bit of difference

#!/bin/bash

#Check if the script is ran by root
SYSTEM_USER_NAME=$(id -un)
if [[ "${SYSTEM_USER_NAME}" == 'root'  ]]
then
    echo 'You are running the script as root'
    exit 1
fi

I would like to point out, both mine and @bobbyiliev suggestion’s would work. It’s really up to you which you decide to choose. What you need to do is to stay consistent. If you use one way, stay consistent and use it through the script/application you are building. It’s gonna be easier for you to read later. :)

Regards, KDSys