Why is usermod -a -G sudo username not working?

Question

During OS installation, I created only one account. Let's call it howdy. I thought it would have sudo privileges but I was wrong.

I scoured the internet and this forum to find out how to add howdy to the sudoers' list. I was under the impression that usermod -a -G sudo username would work. I opened a root terminal and issued the command. I closed it.

Next I opened a normal terminal and issued the following command: sudo gedit /etc/openvpn/update-resolv-conf

The following are the error messages:

howdy@wendy:~$ sudo gedit /etc/openvpn/update-resolv-conf
sudo: unable to resolve host wendy
[sudo] password for howdy: 
howdy is not in the sudoers file.  This incident will be reported.
[sudo] password for howdy: 

Furthermore I discovered that my root password has changed to the password for howdy. This is odd.

So when I opened a root terminal I now had to enter the password for howdy (the original root password did not work) and issued the command visudo and scrolled down to the phrase # Allow members of group sudo to execute any command My account called howdy is not on it.

I need help with the following:

1. Undo the changes brought about by usermod -a -G sudo username, especially to revert the root password to the original password I entered during OS installation. I don't know what the parameters -a and -G do.

2. Show me how to add my account called howdy to the sudoers' list.

Answer 1

This should help you. -a appends to the group and should only be used with -G, which is the groups to append the user. To answer your question fully, to add someone to the sudoers group and to reset the root password:

su
passwd root
Enter new Unix password:
Confirm new Unix password:

Then:

usermod -a -G sudo howdy

Once this is done, you will need to restart in order for the new changes (adding howdy to the sudo group) to take effect.