Code & Pinot: UNIX!

written by nathan on 2015-04-23 in sysadmin

I gave a presentation tonight at Nashville Girl Geek Dinner's Code & Pinot event. We went over some UNIX history and did a bit of command line intro. Action shot:

It was a great event! I had a lot of fun teaching something I'm passionate about (while de-rusting a bit on relating the basics!) and had some great conversation afterwards. I've given the history talk a number of times over the years, but the GGD Nashville crew got to experience my first test of this talk with slides! \o/ You can download my history presentation here. And here is the history of what I typed during the UNIX lesson.

Side note: We discussed the historically famous "Space Travel" game (look it up). But, all I knew was that it was a game...and I'm not a gamer. So, I had to look it up a bit more when I got home. Apparently it let you simulate travel between planets in our solar system and cost about $50-$75 in 1969 money to play a round on the GE 645 running MULTICS! Which is $320-$482 in 2015 money. No wonder re-writing the whole OS on cheaper hardware was worth it. :-P

If any of you were there and would like to know more, here are some good links that I used when re-acquainting myself with UNIX's colorful history and some beginner material:

More History of UNIX

Other Good Intros

Don’t have UNIX to play with? Get it in the browser with JS/UIX!

Cheat Sheets

Beers w/Trey

written by nathan on 2013-05-08 in nashville , timelapse

Trey came to town. So, we had beer. And I made picturefilms. Used a GoPro and the Radian, which had arrived a few days before. Still not great with it, but the results here were fun. Filmed at both Craft Brewed and M.L. Rose. Approximately 250X normal speed.

Thoughts on "negative-Kelvin"

written by nathan on 2013-01-05 in science

Nature: Quantum gas goes below absolute zero.

I thought I had a decent understanding of physics. But after reading this, someone should revoke my 'amateur scientist' card. This (from Wikipedia) helped me understand it:

Since we started with over half the atoms in the spin-down state, initially this drives the system towards a 50/50 mixture, so the entropy is increasing, corresponding to a positive temperature. However, at some point more than half of the spins are in the spin-up position. In this case, adding additional energy reduces the entropy, since it moves the system further from a 50/50 mixture. This reduction in entropy with the addition of energy corresponds to a negative temperature.

This is not about the common notions of hot and cold, this is thermodynamic temperature, which is about entropy and energy. OK, so to me, this amounts to a neat physics trick. The universe will not collapse and our understanding of physics hasn't changed. Hopefully, it'll inspire a few folks (like me) to understand it better. Doing more reading, it reads like this only works in a 'system' of atoms, not with a singular atom. If you can't make a single atom colder than 0.0 kelvin, then the fundamental physics models don't change. Somewhat frustratingly, I see no mentions of anti-gravity, which was the most radical thing said on the article. So, please erase that and any anti-gravity belt predictions from your memory banks.

Speaking of theoretical maximums, another fascinating one is the concept of "absolute hot", which is currently defined as the Planck temperature, (1.416785×10^32^ kelvin). All physics models break down, even things like gravity. And, theory says that the entire universe has already experienced this temperature, a fraction of a second after the big bang. Enjoy that thought.

Further reading:

High-Speed Datacenter Work

written by nathan on 2012-11-08 in sysadmin , timelapse , video

Went to the datacenter last night to build out a few DB servers with 64GB of RAM. And set up a timelapse to record parts of the work. Marc, Brian and I did 2 servers each. You can see some up-close shots of the Dell R710 hardware, though it's quite blurry. Playback is 74 x normal speed.

Wasp Nest

written by nathan on 2012-11-01 in science , video

Found a paper wasp nest today while we were having work done on the house. It was cold out and I thought they were dead...when I set it down in the sun to take a picture, I saw some movement. So, I filmed the little guy trying to get out. National Geographic here I come.

Rain Math

written by nathan on 2012-09-30 in nashville , science

The storm headed our way tonight is predicted to drop 2" of rain over Nashville. If it covers the entire 527 square miles with that amount (on average), that storm would drop 152.8 billion pounds of water. Yay science.

Here's my math:

1 inch of rain x 1 square mile = 65,785 cubic meters = 17,378,742 gallons

Nashville is 527 square miles according to Wikipedia.

A gallon of water weighs 8.35 lb.

So, 2 inches of rain over every inch of Nashville is 2 x 527 x 17,378,742 ....

Which is 18,317,194,068 gallons. Which weighs = 152,948,570,467 lb.

Yikes. I better go start mowing the yard like right now. I don't want to get killed when the rain falls on me

git + sudo + local ssh keys

written by nathan on 2012-05-08 in sysadmin

Some colleagues and I wanted to be able to check out code onto a remote server using our local github ssh keys. And we should be able to do that as any user we please (for example, the deploy user). After a bit of research, I found that it's possible! In short, you use ssh-agent to pass your key credentials on to the remote server and set up sudo to pass those credentials along thru the environments. Let's do this!

I'm on a Mac, which has ssh-agent running by default. Yay! But, you still want to verify that your key is added to the agent:

laptop:~ n8foo$ ssh-add -l  
2048 00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00
/Users/n8foo/.ssh/id_rsa (RSA)

Now, ssh into your remote server using the -A flag to ssh to pass auth along.

ssh -A

Test that ssh's agent auth worked:

[remoteuser@remote ~]$ ssh-add -l  
2048 00:00:00:00:00:00:00:00:00:00:00:00:00:00:00:00
/Users/n8foo/.ssh/id_rsa (RSA)

Your keys should show up. Now, confirm that you can access github with your key from that remote server:

[remoteuser@remote ~]$ ssh -T

Hi n8foo! You've successfully authenticated, but GitHub does not provide
shell access.

OK, now let's enable this so we can switch users with sudo. Sudo needs to pass the SSH_AUTH_SOCK environment variable on through. To do that, add (or modify) the defaults line in /etc/sudoers to look something like this:

Defaults env_keep+=SSH_AUTH_SOCK

You can do this, if you have a default ubuntu sudo config:

# sed -i "s/^Defaults.*/Defaults env_keep+=SSH_AUTH_SOCK/g"

Everything should be working now. Let's test...

[remoteuser@remote ~]$ sudo su - someotheruser  
[someotheruser@remote ~]$ ssh -T

Hi n8foo! You've successfully authenticated, but GitHub does not provide
shell access.

You can now get your git on, directly on your remote machine, as another user. Done!

BCN11 Wrap-Up

written by nathan on 2011-10-16 in nashville

My Space Balloon presentation at BarCamp Nashville went well. I normally would 'wing' a BarCamp talk, showing only the pics/video or show-n-tell. But I realized earlier in the week that I had a lot to cover and only 35 minutes to complete it. I figured some organization of my material might be in order. So, those of you that were there got to witness my first ever keynote presentation. Woo hoo!

I had a number of people tell me that they missed it,  due to collision with blocked-off roads from a footrace that morning or the 9AM timeslot. So, here is the presentation in PDF format, with movies removed:  Space Balloon BCN11 Presentation. If you want to see the movies, they are linked on my blog here.


One other really cool thing that happened yesterday during the talk was Nick Navatta drawing a graphic of the presentation. Seriously cool. He even let me keep the end result, which I shot and put up on flickr.

Here is the full pic:

Space Balloon Presentation Graphic by Nick

Nashville Amazon Web Services User Group

written by nathan on 2011-09-15 in nashville , sysadmin

A few of us are putting together a local Amazon Web Services User Group here in Nashville. The initial idea is to follow a format similar to Portland's AWSUG. Invite local experts, give talks, get together and share stories, etc. Maybe host a yearly event in Nashville, not sure. These are all just ideas at the moment. AWS's most game-changing (and also complex) product is EC2 and I'm guessing that will garner a lot of interest. That's also my area of expertise and interest.

Scheduled for Wednesday, Sept 28th (2 weeks from yesterday), the first meet up would be an informal get together to come up with a simple charter, brainstorm on activities, come up with a list of potential venues and sketch out a general calendar for the next quarter. I figure this can be accomplished after work, across a table of drinks. Yeah?

If you'd like to join....we'll be at the Corsair Taproom from 6pm till about 8pm.

Nashville Amazon Web Services User Group (NAWSUG)
Initial Planning Meeting - Informal w/beer
Sept 28th 2011, 6pm-8pm at the Corsair Taproom

Corsair Taproom Location:
1200 Clinton Street #110
Nashville, TN 37203
Map Link

BarCamp 0b10

written by nathan on 2011-09-13 in nashville

There's been a flurry of activity in Nashville about Bar Camp over the last 48 hours...and 5 years. I won't summarize because it removes the passion. If you care, go read them (referenced at the bottom).

So what do we (the Nashville community) do about it. Well, we act. Earlier today Tim Moses posted this:

I think there is room for an alternate BarCamp that answers your concerns without conflicting with the current BarCamp. BCN may not be true BarCamp format, but it is successful. It may not be tech-heavy, but that seems to be improving in large part by the BCN organizers. Making dramatic changes to BCN would most likely hurt it more than help.

The problem isn't with the existence of BCN or how it operates, but the nonexistence of a tech-focused BarCamp. Many BCN supporters have repeatedly suggested an alternate, but no one has stepped up to do it.

On that note, Nathan Hubbard (ex-Telalinker with true BarCamp experience), and I are organizing BarCamp 0b10, a tech-focused, 2 day, traditional BarCamp to complement BCN. The current plan is to space it far enough from BCN (maybe Spring) to not force a choice between the two. If you like both, go to both, present at both. If not, pick your BarCamp of choice.

We're shooting for a date sometime this spring and looking to things like this and people like this for inspiration and guidance. Initial thoughts are: traditional BarCamp, 2 days (camping!), complimentary to BCN, 'tech focused' but not tech only, simpler and less complex, less organized, etc. Tim and I will announce more via this blog and our twitter accounts (@timmoses, @n8foo) in the next few months. Keep your eyes peeled. Update: we have a new twitter account: @BarCamp0b10 and hashtag #0b10.

Right now, the Nashville community needs to focus on making BarCamp Nashville 2011 awesome. Go sign up. Go to make a difference. Go to see what it's like if you've never been. Don't wait on our event, go act.



  1. Nashville Scene: BarCampNashville Descends Into Online BarFightNashville
  2. Chris Wage: The Not-So-Great Barcamp Schism
  3. Matt George: Clarification on BCN comments
  4. Twitter: BCN_Critic
  5. Countless posts on twitter by the Nashville BCN crew and other tech heavyweights.
  6. Bar Camp Nashville
  7. The Rules of BarCamp
  8. BarCampSD