What are home row arrow keys?

Home row arrow keys are a way of remapping your keyboard to make navigating around your computer faster and more efficient. In this tutorial I will be remapping my ijkl keys to become my arrow keys (up, left, down, right) when I hold a specific modifier key. In this case caps_lock.

Why is this a good thing?

Have you ever noticed how you actually type and move your cursor around files currently? You probably even find yourself reaching for your mouse quite frequently. Look at it carefully, you'll see you do a lot of hand context switching, moving from typing to navigating around back and forth, back and forth. I'm not sure about you, but for me at least, this context switching would cause a lot of issues and misspellings if I misplaced my hand even slightly when switching between the two modes.

To be honest, I never really thought of this as a major issue as it was just one of those things you had to deal with to use a computer. That is until an old coworker turned me onto home row arrow keys. He was seriously a wizard! We would pair program and his speed and efficiency moving around files, slicing/pasting text and typing were blazing fast! It was incredible! Even outside of his ide he was a ninja. Opening other programs, navigating around them, especially web browsing. I was astonished.

He was using a nifty mechanical keyboard and I assumed it was that but when he explained to me how he remapped his ijkl keys and that was how he was able to perform such fast actions I knew I had to try this out. He told me how to do it in a few easy steps and I've since refined it a bit but it's basically the exact same setup. Huge shout out to this wiz for changing my life and reducing the translation time from thought to computer action. You've saved me countless hours over the years, my dude!

Getting Started

DISCLAIMER: this is only for mac at this time, if you know how to set it up for windows or linux let me know I'm very interested!

If you just want a copy of json config file click here

Download and Install Karabiner-Elements

Karabiner Elements is this amazing application that gives you a great and flexible way of remapping your keyboard layout. You can either build it from the source there or download the installer here.

Once downloaded, go ahead and install it. You may need to give it some extra privileges depending on your configuration.

Setup key remappings

We'll start by setting up a new profile. Open the app:
cmd+spacebar then type karabiner-elements and go to the app's preferences

From the menu screen select the profiles tab

Create a new profile and name it whatever you want.

Hit enter to save the name and then toggle to the new profile.

Open your ~/.config/karabiner directory and you should now see a karabiner.json file. We will need to open and edit this file. (If it's not there, you can simply create it and copy in my config above.)

Looking through the file you should see that it contains a profile section with all the profile names listed in the profiles tab.

Break down

Okay so this file may be a bit confusing at first but the key things here are the complex_modifications and simple_modifications.

You can think of simple_modifications as basic key remappings.
ie. change key a to act as key b etc.

The complex_modifications are macros. Combinations of keypresses that together, will perform certain actions.

Simple Modification

Let's start with the simple_modifications that we need to change since that's an easy way to get more comfortable.

As you can see the simple_modifications is an array so let's add a new item to it.

...
"simple_modifications": [
  {
    "from": {
      "key_code": "caps_lock"
    },
    "to": {
      "key_code": "left_control"
    }
  }
]
...

All we're saying here is that we want Karabiner to overwrite the caps_lock key ("from") on our keyboard with left_control ("to"). (As far as I know you have to specify the control orientation and can't just do control for any kind of ctrl key.)

Once the file is saved. Use the profile selector to swap between Default and our new profile to refresh the changes. You should now see your caps_lock key now acts as your ctrl key.

Pretty simple right?

Complex Modification

Alright with that out of the way let's get to the good stuff.

We're interested in the the rules section of the complex_modifications, we can ignore the parameters section for now. (But I do recommend looking that over at some point).

We are going to create a new rule, you can call it whatever you like but I named mine: Change left_ctrl+jikl to arrow keys

You can copy and paste this into the rules array:

{
  "description": "Change left_ctrl+jikl to arrow keys",
  "manipulators": [
    {
      "from": {
        "key_code": "j",
        "modifiers": {
          "mandatory": ["left_control"],
          "optional": ["any"]
        }
      },
      "to": [
        {
          "key_code": "left_arrow"
        }
      ],
      "type": "basic"
    },
    {
      "from": {
        "key_code": "k",
        "modifiers": {
          "mandatory": ["left_control"],
          "optional": ["any"]
        }
      },
      "to": [
        {
          "key_code": "down_arrow"
        }
      ],
      "type": "basic"
    },
    {
      "from": {
        "key_code": "i",
        "modifiers": {
          "mandatory": ["left_control"],
          "optional": ["any"]
        }
      },
      "to": [
        {
          "key_code": "up_arrow"
        }
      ],
      "type": "basic"
    },
    {
      "from": {
        "key_code": "l",
        "modifiers": {
          "mandatory": ["left_control"],
          "optional": ["any"]
        }
      },
      "to": [
        {
          "key_code": "right_arrow"
        }
      ],
      "type": "basic"
    }
  ]
}

For this rule all we're saying is that for each of the jikl keys if they're pressed while left_control is pressed, make that key act as the corresponding arrow key. The optional parameter is necessary as it will map any additional modifiers to be allowed to be passed along to our combination as well. So things like left_control + shift + j will now act like shift + left_arrow etc.

Refresh the profile again and since we just remapped our caps_lock to be left_control you should now be able to navigate around your computer using caps_lock + jikl!

If it's not working for you, you can copy and paste my settings into your karabiner.json file from this link and then refresh to see if it works.

The End!

That's it! I hope you enjoyed this and that it helps speed up your workflow as much as it has mine. If you have any questions or comments for me feel free to leave them below.

Happy coding!

Extra topics

Why ctrl and not fn

Okay you may be thinking, why set caps_lock as ctrl and not fn or something more complex so it doesn't interfere with other key combos you rely on? That is a fair point and you're more than welcome to modify the json config to your liking. The reason I stick with ctrl is because Unix based OS's come with some built in navigation shortcuts automatically that utilize the ctrl key.

Some that I use all the time are ctrl + a and ctrl + e for navigating to the beginning and ending of a line easily. By swapping to ctrl and not something else I keep cursor navigation consistent across my entire computer, regardless of the application I'm in. (Try going to your url bar in your browser and hitting ctrl + shift + e)

Sortcut reference - https://www.computerhope.com/ushort.htm

Downsides to the switch

There are some downsides to making this switch. I don't think they're big but they are worth noting:

Becoming reliant on setup

By making this swap and becoming reliant on this setup I now find it hard to use other computers. Not terribly difficult, but I definitely start YELLING pretty quickly when I first start typing on someone else's computer. I then remember to use the real arrow keys and then it just feels uncomfortable to navigate around like someone has put weights on my thoughts.

Reliant on third party app

When I first made the transition Karabiner-Elements wasn't around and it's predecessor Karabiner wasn't as easy to setup. It also didn't play as well with OSX and when I upgraded to Sierra it stopped working completely. This sucked and I got very scared I would have to go back to my old life of slow navigation. Thankfully elements was made with the intention of being long term, but it's still something to keep in mind that I am now dependent on this 3rd party application.