Check If a script is executed as root?

Question

I have a script that requires root privileges. I have to execute it either via sudo or from an account with uid 0 (e.g. root).

If the script is not executed with sufficient rights then I want that script to echo "Run as Root" and exit 1.

How can I achieve this ?

Answer 1

#!/usr/bin/env bash
if [[ $EUID -ne 0 ]]; then
   echo "This script must be run as root" 
   exit 1
fi

// Rest of the script here

Source.

EUID is the effecvtive UID the script is running as.

[[ ne ]] is a test on not equal.

0 is the uid of root (or rather, the uid you want. The name root is the most often name but that can be changed and there can be multiple accounts with uid 0

Answer 2

You could also make the script just executable by root.

chmod 700 script (just the file owner can run the script)

chown root:wheel script (set file owner to root)