---
title: "Write a Script"
url: https://docs.catalyst.zoho.com/en/cli/v1/scripts/write-script/
description: "Catalyst provides the functionality for automating CLI and terminal command executions during the testing or deployment process in the form of scripts."
last_updated: 2026-08-17T12:16:04Z
service: All Services
type: general
---

# Write a Script

### Introduction

You can define and execute scripts for the client and the functions of your project. You can execute Catalyst CLI
commands and terminal commands of your local environment through scripts.

You must write the scripts in the `scripts` field of the `functions` or
`client` scope in the [
`catalyst.json` ](https://docs.catalyst.zoho.com/en/cli/v1/project-directory-structure/catalyst-json/) file present in the root of your project directory. This file contains the configuration and target information of your project directory components. A sample code structure of the `catalyst.json` configuration file is shown below.

![CLI Write Script](https://catalyst-docs-development.zohostratus.in/images/cli/catalyst-scripts/catalyst_cli_scripts_catalyst_json.webp)

### Sample Script

Let's discuss the script shown in the picture above. The code of this `catalyst.json` file defines
two lifecycle scripts and two custom scripts. The execution of the lifecycle scripts will run the custom scripts. The
scripts here are included inside the client's scope, because they are defined for the client component of the project.

The code is given below:

```json
{
"functions": {
"targets": [
"catly"
],
"ignore": [],
"source": "functions"
},
"client": {
"source": "client/app/build",
"ignore": [],
"scripts": {
"packageJson": "cd client && cp client-package.json app/build/",
"build": "cd client/app && yarn install && yarn build",
"preserve": "catalyst run client:build && catalyst run client:packageJson",
"predeploy": "catalyst run client:build && catalyst run client:packageJson"
}
}
}

```

When you execute a custom script inside a lifecycle script using the [ ` catalyst run ` ](https://docs.catalyst.zoho.com/en/cli/v1/scripts/run-script/)  command as shown in the example above, you must specify the component it is being executed for. This is necessary if, for example, there is a `cd` (change directory) terminal command to be executed. The root of that component's directory will be considered as the directory the change directory command is executed from.

The logic flow of the scripts written above is as follows:

1. When you execute the `catalyst serve` or `catalyst deploy` command for the
client component, the `preserve` or `predeploy` scripts are initiated
respectively, before running the command.

2. Both the `preserve` and `predeploy` scripts contain the same command
executions. The first action is the `catalyst run client:build` command, which executes the
`build` custom script for the client component. The second action is the catalyst run
client:packageJson , which executes the `packageJson` script for the client component.

3. The `build` custom script performs the following actions in sequence:

    * The terminal is navigated to the `client/app` directory.
    * The `yarn install` command is executed to install Node.js dependencies using the Yarn package manager.
    * The `yarn build` command is executed to build the client application.

4. The `packageJson` custom script performs the following actions one after the other:

    * The terminal is navigated to the `client` directory.
    * The `client-package.json` file is copied from the client directory and is pasted to the `app/build` directory.

After these scripts are executed, the components are served or deployed.