How to Make a Programming Cheat Sheet

It's always delightful when search results answer our question in fewer steps than we expected. Programming language Cheat Sheets are no exception. Naturally, our community would love to encourage more of them (we even made a table).

Cheat Sheets are the easiest type of Instant Answer to contribute. There are several kinds you can make: reference cheat sheets, language cheat sheets, key bindings, in addition to programming cheat sheets. In this tutorial, we'll learn how the Regular Expressions Cheat Sheet was made.

How Cheat Sheets Work

Cheat Sheets trigger when users search for their topic together with keywords determined by their template type, name, and aliases (check out the full list of terms). For example, searching for "regex cheat sheet" would trigger the Regex Cheat Sheet Instant Answer.

Learn more about how to trigger your Cheat Sheet in the reference.

Anatomy of a Cheat Sheet

Cheat sheets only require you to add one file with the information to present. In our case, that would be regex.json.

File Purpose Location
regex.json Specify cheat sheet info and display settings Placed inside the Cheat Sheets Goodie directory: zeroclickinfo-goodies/share/goodie/cheat_sheets/json/

Set Up Your Development Environment

Before we begin coding, we'll need to set up our development environment. There are three main steps:

  1. Fork the Goodie repository on (How?)
  2. Set up the DuckDuckHack environment on (How?)
  3. Clone your Github fork onto the Codio environment. (How?)

If this is your first time developing an Instant Answer, check out our detailed, step-by-step guide to getting your development environment set up.

Create the Instant Answer Page

If you're just using this walkthrough to learn and practice for now, you can skip this step. This is important only if you plan to submit what you're working on.

Every Instant Answer on has its very own Instant Answer Page. These are the home base for planning, collaboration, and metadata. Instant Answer pages also show any Github issues and let you know what stage the Instant Answer is in.

When done coding, you'll use the URL of your Instant Answer page when submitting your contribution.

Now let's start coding!

Generate Cheat Sheet Boilerplate File

Back in Codio, load the terminal:

Next, change into the Goodie repository's home directory, zeroclickinfo-goodies:

[01:07 PM codio@border-carlo workspace ]$ cd zeroclickinfo-goodies

Before doing any coding, it's recommended you work from a new, separate Git branch and not master. A separate branch allows you to keep your repository up-to-date, and work on multiple pull requests at one time.

The branch name can be anything you like, for example:

[08:18 PM codio@border-carlo zeroclickinfo-spice {master}]$ git checkout -b regex1

The duckpan tool helps make and test Instant Answers. To create the boilerplate specific to a cheatsheet, run duckpan new --cheatsheet:

[01:08 PM codio@border-carlo zeroclickinfo-goodies {regex1}]$ duckpan new --cheatsheet
Creating a new Cheat Sheet Instant Answer...
Please enter a name for your Instant Answer:

Type regex1 (since regex already exists in the repository, we'll add a character for this tutorial). If the name contains more than one word, separate them with a space. The tool will do the rest:

Please enter a name for your Instant Answer: regex1
Created files:

That's convenient: The single file we need has been created, named, and located in the proper place in the repository. Internally, it contains correct boilerplate to save us time.

Open the File for Editing

Let's locate the regex1.json file we just created. In Codio, use the left-hand panel to navigate to the /zeroclickinfo-goodies repository directory. Then use the file tree to click into the /share/goodie/cheat_sheets/json directory. Finally, double click regex1.json to edit it.

Add Metadata

Let's add the metadata for our cheat sheet — the information that helps classify, organize, and display our Instant Answer. Start by entering a unique id for your Cheat Sheet. This will already have been done for us, and there's no need to change anything:

    "id": "regex1_cheat_sheet",

Next, under the id, add a name and description for your Instant Answer (feel free to copy and paste):

    "name": "Regex1",
    "description": "Regular expression syntax",

Let's cite a source and link for our information, whenever possible, under metadata (feel free to copy and paste):

    "metadata": {
        "sourceName": "Cheatography",
        "sourceUrl": ""

Add Cheat Sheet Settings

Right now, since we named our file regex.json, our Cheat Sheet will trigger on phrases like 'regex cheat sheet'. If we want it to trigger on words other than 'regex', we can specify aliases. Add the aliases property under metadata:

    "aliases": [
        "regexp", "regular expression", "regular expressions"

Only use aliases to specify additional names for your topic (e.g. 'regexp') and not trigger phrases (e.g. 'regexp guide'). This is because any aliases will be automatically combined with the standard set of cheat sheet trigger words.

Conveniently, the file name is automatically used as the first alias (in this example "regex"). There is no need to include it as an alias.

Next, we decide the form in which the cheat sheet will be displayed. There are multiple cheat sheet template types you can choose from.

We'll choose the code template, because it fits our content the best. Here is a sample of what the code template looks like:

Add it to our file as follows:

    "template_type": "code",

Fill Out Content

Now it's time to fill in our Cheat Sheet's helpful content. This is done as an object, under the sections property. Each section is a key-value pair of the section's name, and an array:

    "sections": {
        "Assertions": [
                "val": "Lookahead assertion",
                "key": "?="
            }, {
                "val": "Negative lookahead",
                "key": "?!"
        "POSIX Classes": [
                "val": "Uppercase letters [A-Z]",
                "key": "[:upper:]"
            }, {
                "val": "Lowercase letters [a-z]",
                "key": "[:lower:]"

Each section's array lists objects, each with key and val properties. These contain the actual visible content of the cheat sheet.

Here we only included a small sample, but you can see the full amount of content in the live code).

Wondering about special characters, or how to designate separate key presses? The full JSON syntax for entering this information is documented in the Cheat Sheets reference page.

Finally, we can specify precisely in what order to display sections using the section_order property. Paste the following in the section_order property:

    "section_order": ["POSIX Classes", "Assertions"],

In order to be displayed, every section in sections must appear in section_order.

Great work! Your cheat sheet is ready to validate and test.

Validate Your Cheat Sheet

Let's make sure our contribution is formatted properly and follows all rules. If something should fail, please refer to the Cheat Sheet reference page.

  1. Validate your JSON: You can easily do this by copying your file contents and pasting it into JSON Validator to make sure it's valid JSON.

  2. Validate your Cheat Sheet Code: The following command will check the file formatting and make sure everything is consistent, and all required properties are present. For example, in addition to formatting, it will check that all sections declared also exist, and vice versa.

    Since the Cheat Sheet Goodie already exists, the test file is already written. All you need to do is enter the following into your Codio terminal:

     duckpan test CheatSheets

And scroll up to your cheat sheet to make sure there are no warnings!

That's it! You're ready to try out your cheat sheet.

Interactively Test Your Cheat Sheet

Let's see our Cheat Sheet in action. To do this, we'll create a test server that will allow you to view your Instant Answer as it would appear above DuckDuckGo search results.

  1. In Codio, open your Terminal by clicking on Tools > Terminal.

  2. Change into the zeroclickinfo-goodies directory by typing cd zeroclickinfo-goodies at the command line.

  3. Next, type duckpan server and press "Enter". The Terminal should print some text and let you know that the server is listening on port 5000.

     Starting up webserver...
     You can stop the webserver with Ctrl-C
     HTTP::Server::PSGI: Accepting connections at http://0:5000/
  4. Click the "DuckPAN Server" button at the top of the screen. A new browser tab should open and you should see the DuckDuckGo Homepage.

  5. Search for 'regex1 cheat sheet'. You should see something like this:

You should see your cheat sheet show up in the search results!

When you're done testing, go back to the Terminal, and press "Ctrl+C" to shut down the DuckPAN Server. The Terminal should return to a regular command prompt.

Congratulations! Want to create an Instant Answer to go live on Learn more about submitting your idea.

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