Anyone who spends time in a shell (sh, bash, zsh) knows that aliases can greatly help with productivity through the reduction in typing and typing mistakes. Most shells come with some already set, such as ll for ls -alF, so you can see details of the current directory: You can add any others yourself to […]
Author Archives: markcallen
Connecting Feature Flags with DORA Metrics
I wrote an article for Devcycle on how to use feature flags to improve DORA metrics: https://devcycle.com/blog/connecting-feature-flags-and-dora-metrics
Non-boolean Feature Flags
I wrote an article on how to use a non-boolean feature flag to change a page at a specific time using Devcycle. You can find it here: https://devcycle.com/blog/using-non-boolean-feature-flags
VIM & Tmux Basics
Why? Vi (vim) is the only editor you can be guaranteed to have on a Linux machine. If you ever have to log into a server, or container, to see what’s going on or make changes this will be all you’ll have. It will save your life. Tmux allows you to use the terminal without […]
Upgrading from Ubuntu 12.10 to 14.04
Seems that a few of my instances in AWS were originally setup using Ubuntu 12.10. Don’t know how that happened, but anyways. Now that 12.10 is no longer support you can’t just upgrade. So the solution is to use the old.releases.ubuntu.com site and update/upgrade from there. sudo cp /etc/apt/sources.list /etc/apt/sources.list.bak sudo sed -i -re ‘s/us-west-2.ec2.archive.ubuntu.com|security.ubuntu.com/old-releases.ubuntu.com/g’ […]
Vagrant machine status
If you need to get the status of a vagrant machine you can run the following in a command window: vagrant status aws –machine-readable | awk -F”,” ‘{if ($3 == “state”) print $4;}’ Will output: running if the machine is running or not_created if it is not.
AWS SNS and SQS Example using NodeJS
Using SNS and SQS and Example using NodeJS Motivation I wanted to test out using the new aws-sdk with Amazon Web Services (AWS) SNS and SQS services. It is now possible to subscribe queues to topics therefore creating a pub/sub style system without any system configuration work. Setup at AWS I created a new IAM […]
OpenSUSE 11.1 for Vagrant
Seems that last week I needed an openSUSE 11.1 VM to test out some chef scripts. Vagrant Cloud which is a great place to find Vagrant VMs didn’t have one, so I decided to create one. Start first by downloading and installing packer an incredible tool for creating virtual machines from templates and scripts. I used the […]
Dependency Walker
Currently working out a build system for a windows application. Found this was helpful when trying to figure out which dlls where being used by some dlls created a long time ago. Dependency Walker (depends.exe) Home Page. Shows the dependency hierarchy of the dll or exe.
Nginx Deny IP
This is a quick way to deny an ip address accessing your nginx server. Create a new file in /etc/nginx/conf.d called blockips.conf Add the following to the file: deny <bad ip>; Then restart nginx. The log file will now show 403’s for the IP address. For more info see: http://www.cyberciti.biz/faq/linux-unix-nginx-access-control-howto/