The Big Permissions Scare :O

I gave myself a pretty big scare yesterday. I was happily going along, using my computer like usual when I started to run into some internet problems. “Oh, I haven’t changed my DNS servers today,” I thought — sometimes the DNS doesn’t seem to work quite right here and I have to use OpenDNS if I want to go to any websites. So, since I’m running Ubuntu, I opened up System->Network, clicked on Authorize, and entered my username and password. I waited expectantly for it to authorize me, but it gave me a message that said “Error: could not authenticate,” or something along those lines.

“Whaaaaaat?” I said aloud, to no one in particular. My computer had been irregularly slow all day so I thought maybe something really weird was going on. However, I had other things on my mind at the time and decided I could do without messing with it at the moment.

Later on, I decided I wanted to upgrade my packages. I typed in sudo apt-get update, typed in my password, and this little gem popped up: sajo is not in the sudoers file. This incident will be reported. “OH CRAP!” was now running through my mind. Then it dawned on me — I had been having some permissions problems with some command line utilities I was using the previous day (it wanted to generate files in a folder owned by “www-data”) so I had added myself to the group “www-data.” I had used the usermod command with the -G option which allows one to specify a list of groups for the user. However, when I went back to the documentation I saw that I had not read the entire explanation of the option and that in order to avoid having the command remove all the groups one was previously a part of, the -a option must be specified as well. Of course, since I had stupidly not used the -a option, I had removed myself from the “admin” group which was my ticket into the realm of the “sudoers.”

Fortunately, all I had to do was boot into recovery mode and add my user account to the appropriate groups once again, but man was I scared there for a bit. So let this be a lesson to all – read the entire documentation for whatever command options you plan on using.