In this quick setup guide we will cover how to setup a basic scripting environment for both Mac and Windows. It will streamline your workflow by allowing you to code in your favorite text editor, and run your scripts from the Terminal (OSX) or Command Prompt (WIN) directly in After Effects via a simple command.
Note: This setup is an alternative to using the Adobe ExtendScript Toolkit (ESTK - Adobe’s integrated development environment (IDE) for programming ExtendScript). It is a personal preference whether to use the provided toolkit or your custom editor.
Let's Jump right in
Open you editor of choice. Let’s add a quick alert snippet - we will use this to check if the script is running properly once launched. Feel free to customize you alert message.
alert("Script OK");
Save the script as alert.jsx - notice the extension… After Effects scripts must have this extension in order to be run in AE.
MAC Setup
After Effects on Mac does not currently have the capabilities to run scripts directly via Terminal. We can remedy this with a quick workaround using Applescript - Apple’s own scripting language that allows you to automate tasks on your Mac OS.
Open the Script Editor app or search for it in Spotlight. Then paste the following code, and save:
on run argv
tell application "Adobe After Effects CC 2019" --specify your version of AE here.
DoScriptFile item 1 of argv
end tell
end run
Note: Make sure you specify your version of AE in the script. If you are not sure, navigate to your Applications folder or wherever your AE version is installed and check the version name there.

Understanding the Applescript code
In essence, we are telling (tell) our version of After Effects to run the script (DoScriptFile) that we are specifying. The path to the script is retrieved from the argument (argv) that is passed once we will execute the code (in the next step...).
Let's move on by opening the Terminal app, then type in
osascript
Hit Spacebar once. Now drag and drop your Applescript file into the Terminal window. Next, repeat the drag and drop action but with your alert.jsx file instead.
Your command should look like this:
osascript path/to/yourApplescript.scpt “path/to/alert.jsx"
Note: The quotes that surround the jsx file path ensure that the path is passed as an argument and can be referenced inside the Applescript code (in our case it is passed to the DoScriptFile function that launches the script) - if you dropped a script file path containing spaces in your Terminal window, those spaces will be automatically escaped with a backslash: space\ here
. Since we added the quotes already, we don't need to escape the spaces. But if we do, Applescript will assume that the backslashes are part of the file path so won't find your script. Make sure to remove any added backslashes within your quoted filepath.
Now hit Enter. After Effects should launch and, if all is working, it should run our alert.jsx script - you should receive an alert popup with the message you specified.

That’s it!
WINDOWS Setup
On Windows, After Effects comes installed with an executable that can be used to run scripts via Command Prompt.
First locate the AE executable named AfterFX.exe. This should be found in C:\Program Files\Adobe\yourVersionOfAE\Support Files\ - replace yourVersionOfAE with your current version of After Effects e.g. “Adobe After Effects 2019”.
Open Command Prompt. Drag and drop the AfterFX.exe executable into the Command Prompt window then hit Spacebar and type -r
, hit Spacebar again and repeat the drag and drop but this time with your alert.jsx file. Your command should look similar to this:
path/to/AfterFX.exe -r path/to/alert.jsx
Now hit Enter. After Effects should launch and, if all is working, it should run our alert.jsx script - you should receive an alert popup with the message you specified.

Done!
Quick tips
Previous Command
In both Mac Terminal and Windows Command Prompt - you can call your previous command by pressing the up arrow key. Then Enter.
Command History
The following commands allow you to retrieve a list of previously executed commands:
MAC - in Terminal, type history
and press Enter.
WIN - in Command Prompt press F7. Alternatively, type doskey /history
and press Enter.
Useful Links and Resources
After Effects Scripting Reference:
http://docs.aenhancers.com/
After Effects Scripting Forum & Community

Editors
Adobe Extend Script Toolkit (Direct Download), then search for Extendscript Toolkit CC
Brackets Editor:
