Category Archives: Unix

Mac OS X Programming Unix

Mac DevOps Conference

There’s another new conference in town! Well, not my town, but Vancouver. MacDev Ops is a hot topic. One that will only increase in the coming years. Thanks to Mat X and Brian Warsing for bringing about a brilliant conference.

Screen Shot 2015-03-23 at 10.43.50 PM

The conference will be held on June 19, 2015 and is an easy $99 if you sign up soon. Also, submit a talk if DevOps is your thing. They’re looking to bring the following topics to the table:

  • Puppet, Chef and other automation from Desktop to Cloud and back
  • Software deployment with Munki and AutoPkg: the app ecosystem surrounding it
  • Cool tools: demo of awesome Mac Admin projects from GitHub
  • DevOps: How to adopt Automation and Best practices in IT operations
  • Dev skills: workshops on Ruby, Git, Python, Javascript for Mac Admins
  • MDM: Profiles and Mac configuration management in the cloud

This is sure to be a good one. Check it out here!

Ubuntu Unix

See Version Information In Linux

There are a number of ways to see information about what version of Linux that you’re running on different

cat /etc/lsb-release

Which returns the distribution information, parsed as follows:

DISTRIB_DESCRIPTION="Ubuntu Precise Pangolin (LTS)"

LSB_release can also be run as a command, as follows:

lsb_release -a

Which returns the following:

No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu Precise Pangolin (LTS)
Release: 12.04.5
Codename: precise

lab_release can be used as a command as well:

cat /etc/

Which returns:

Ubuntu Precise Pangolin
(development branch)

In Debian, you can simply look at the version file:

cat /etc/debian_version

Which returns the following:


Or Red Hat Enterprise can also be located with /etc/

cat /etc/

With many variants, including OS X, you can also use uname to determine kernel extensions, etc:

uname -a

The thing I’ve learned about Linux is that there’s always a better way to do things. So feel free to comment on your better way or favorite variant!

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Install Pow for Rails Testing On OS X

Pow is a Rack server for OS X. It’s quick and easy to use and lets you skip that whole update an Apache file, then edit /etc/hosts, ethane move a file, then run an app type of process. To get started with Pow, curl it down and pipe it to a shell, then provide the password when prompted to do so:

odr:~ charlesedge$ curl | sh
% Total % Received % Xferd Average Speed Time Time Time Current
Dload Upload Total Spent Left Speed
100 9039 100 9039 0 0 10995 0 --:--:-- --:--:-- --:--:-- 10996
*** Installing Pow 0.5.0...
*** Installing local configuration files...
*** Installing system configuration files as root...
*** Starting the Pow server...
*** Performing self-test...
*** Installed

For troubleshooting instructions, please see the Pow wiki:

To uninstall Pow, `curl | sh`

To install an app into Pow, create a symlink to it using ln (assuming ~/.pow is your current working directory):

ln -s /path/to/myapp

Then just open the url, assuming my app is


Pow can also use ~/Library/LaunchAgents/cx.pow.powd.plist to port proxy. This allows you to redirect different apps to different ports. When pow boots, it runs .powconfig, so there’s a lot you can do there, like export, etc. Once you’re done testing out pow, if you don’t decide it’s awesome, remove it with the following command:

curl | sh

Ubuntu Unix

Linux and Free Memory Space

The free command in Linux is used to show memory utilization. When run without any options, you can see the used and available space of swap and physical memory. By default, the option is displayed in kilobytes but when run with a -b option it is shown in bytes or -m will show in megabytes or -g in gigabytes or -t in terabytes. So to see the free space in bytes run the following:

free -b

The -o option shows the output adjusted for the buffer. The -t option also adds a total column as well as a line for total that shows swap and physical, combined. The -s will update the output and is followed by a number of seconds. To see the number of times it happened, use the -c option. So to see the output every 60 seconds:

free -cs 60

The low and high stats are shown using the -l option:

free -l

As with many commands, you can see the version of the command using the -V option:

free -V

Finally, use the –help option to see the available options, no matter the version or OS.

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Opposite Day: Reversing Lines In Files

The other day, my daughter said “it’s opposite day” when it was time to do a little homework, trying to get out of it! Which reminded me of a funny little command line tool called rev. Rev reads a file and reverses all the lines. So let’s touch a file called rev ~/Desktop/revtest and then populate it with the following lines:


Now run rev followed by the file name:

rev ~/Desktop/revtest

Now cat it:

cat !$

Now rev it again:

rev !$

You go go forward and back at will for fun, much more fun than homework… Enjoy!

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Manage Apex Domains In OS X

OS X Server supports running a traditional bind implementation of DNS. You can define a record for most any name, including,,, etc. You can use this to redirect subdomains. In this example, we’ll create an A Record to point to without breaking other subdomains. To get started, let’s use the DNS service in the Server app to create The reason for this is that OS X will then create a zone file for If we created instead, then OS X would automatically create, which would break the other subdomains. To do so, open Server app and click on the DNS Service. Then click on the plus sign to create a new record.

Screen Shot 2014-09-23 at 10.55.58 AM

Now, if you restart dns and ping you should see the referenced IP. To then change, we’d edit the zone file stored at /Library/Server/named/ This file will look like this when you first open it: 10800 IN SOA (
2014092301 ; serial
3600 ; refresh (1 hour)
900 ; retry (15 minutes)
1209600 ; expire (2 weeks)
86400 ; minimum (1 day)
10800 IN NS 10800 IN A

We’ll add an a record for 10801 IN A

Now, to change the apex record, you’d just replace the name you’ve been using with an @:

@ 10801 IN A

Good luck!

Ubuntu Unix

Installing the Docker for OpenStack Heat

Docker is an engine that automates deploying applications as highly portable, self-sufficient containers, independent of hardware, language, framework, packaging system and hosting provider. Heat is the main project used when it comes to OpenStack orchestration. There is a Docker plugin for Heat. To install this plugin, you’ll need to use the stable/icehouse branch (which seems like what’s made the tool so mature rather than simply being available for Nova) to install Heat via apt-get install. Once downloaded, extract the contrib/docker folder and delete the tests directory. Then copy the contrib/docker folder to the OpenStack controller. Here we’ll put it at /usr/lib/heat directory. This results in the path of /usr/lib/heat/docker/docker. Next, install python-pip:

apt-get install python-pip

Then check the installer requirements:

pip install -r requirements.txt

Then edit the heat config, likely at /etc/heat/heat.conf. Here, provide the plugin in the plugin_dirs section as:


Then reboot and check the resource type listing:

/usr/lib/heat/heat resource-type-list

If you see DockerInc::Docker::Container, you can deploy Docker containers.

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Make iMovie Work With Network Volumes

I work with a lot of network storage and video world stuff. While most in the editorial world prefer FinalCut, Avid, Adobe and other tools for video management, I do see the occasional task done in iMovie. By default, iMovie doesn’t support using assets stored on network volumes. However, you can make it. To do so, just use defaults to write with a boolean allowNV key marked as true:

defaults write allowNV -bool TRUE


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