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Sudoers File Explained

You are probably wondering how the sudoers file works. Here’s a simple explanation.

Command

username host=(user:group) tag:commands

Explanation

    • username – the specified user allowed to run commands.
    • host – the specified host the command is allowed to run.
    • user – specifies which users can use the command.
    • group – specifies which groups can run the command.
    • tag – the option allowed. NOPASSWD
    • command – the command allowed to run.

Examples

root    ALL=(ALL) ALL
username ALL=(ALL) ALL
john test=(ALL) NOPASSWD: /bin/useradd
jane ALL=(sales) NOPASSWD: /bin/sh
%sudo ALL=(ALL) ALL
%adgroup ALL=(ALL) ALL

Remove Sudo Password

Removing sudo password is typically not a good practice. If you’re a seasoned system administrator, or you’re the only one using your own desktop, being prompted for a sudo password can get really annoying. Here’s how to stop getting prompted every time you run sudo.

Run visudo. 

sudo visudo

Edit the sudo line and set to below.

%sudo ALL=(ALL) NOPASSWD: ALL

Save file.

Wheel Group

Here’s an alternate way to give Linux users sudo access by adding them to the wheel group. Most Linux systems come with the wheel group already predefined. By adding users to the wheel group, they now have the ability to sudo and run root commands. The wheel group is in the sudoers file for Redhat, Centos, Debian and Ubuntu.

usermod -aG wheel username