How to Automate Homebrew Updates with a Script in macOS

Edited 4 weeks ago by ExtremeHow Editorial Team

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Homebrew is a popular package manager for macOS that allows users to install, manage, and update software via the command line. It's incredibly handy for managing software, but for users who manage a large number of packages, manually keeping everything updated can become a cumbersome task. Automating this process can save time and ensure that all your packages are up to date with the latest versions, giving you new features and security updates. In this guide, we'll learn how to automate Homebrew updates using a script in macOS.

Understanding Homebrew and its update mechanisms

Homebrew simplifies the installation process of software by compiling the app source code. It manages dependencies automatically, making it easier for you to focus on the actual development work rather than setting up your environment. When you install Homebrew, it creates a directory in your system where it can store all the packages (or "formulas" as they are called in Homebrew terminology).

Homebrew has three main components:

• Homebrew Core: The core set of packages.
• Homebrew Cask: Used to manage graphical applications.
• Homebrew Services: Used to manage launchd services.

Updating Homebrew involves two primary steps:

1. Updating Homebrew itself.
2. All installed packages and casks are being upgraded.

This can be done manually by running commands in the terminal, but automating these steps with a script can simplify the process considerably, especially if you have a routine you want to follow for regular updates.

Prerequisites

Before proceeding with automation, make sure you have Homebrew installed on your macOS. You can check this by opening the Terminal application and running:

brew --version

If Homebrew is installed, this will print the version you have. If not, you'll need to install it first by running:

/bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/HEAD/install.sh)"

Creating a script to automate Homebrew updates

Now, let's write a script that will automate the update process. We will use a shell script for this task as it is compatible with macOS and can be easily executed from the terminal or automated using cron jobs or launchd.

A step-by-step guide to creating a script

Step 1: Open the text editor

First, you'll need a text editor to write the script. You can use TextEdit, nano, vi, or any other text editor of your choice available on macOS.

Step 2: Write the script

Enter the following lines to create a basic script to update Homebrew:

#!/bin/bash
# Update Homebrew itself
echo "Updating Homebrew..."
brew update
# Upgrade all installed formulae and casks
echo "Upgrading installed formulae and casks..."
brew upgrade
# Cleanup old versions
echo "Cleaning up old versions..."
brew cleanup
# Output message of completion
echo "Homebrew update process completed!"

This script performs the following tasks:

• brew update: Updates Homebrew along with the formula catalog.
• brew upgrade: Upgrades all installed packages (sources) and casks.
• brew cleanup: Removes old versions of sources.

Step 3: Save the script

Save the file with a meaningful name like update_brew.sh. Remember the directory where you saved this file, as it will be needed later to execute or schedule the script.

Step 4: Make the script executable

To run your script, it needs to be executable. Open the terminal and navigate to the directory where you saved your script. Use the chmod command to make it executable:

chmod +x update_brew.sh

Testing the script

Before you set the script to run automatically, you should run it manually once to make sure everything works correctly. In the terminal, navigate to the directory where the script is located and execute this:

./update_brew.sh

If the output indicates that Homebrew and all packages were successfully updated without any errors, you are ready to automate the script.

Automating script execution

There are a few ways to automate script execution on macOS. The two most common ways are using cron jobs and using a launch agent (launchd). We'll explore both, and you can choose the method that best suits your needs.

Using Cron Jobs

Cron is an old scheduling tool available on Unix-like operating systems, including macOS. You can use it to schedule the update_brew.sh script so that it runs at regular intervals.

Setting up a cron job

1. Open the Terminal application.
2. Type crontab -e to edit the cron jobs for your user account. This will open a file that lets you schedule commands.
3. To schedule the script to run at a certain time, add a new line at the bottom of the file with the following content. For example, to run it every day at 2 pm, you could add:

0 2 * * * /path/to/update_brew.sh

In this line, replace /path/to/update_brew.sh with the actual path to your script.

The components of a cron job setup specify:

• Minutes: 0
• Time: 2 (2 AM)
• Day of the month: * (any day)
• Month: * (any month)
• Day of the week: * (any day)
• Command to be executed: /path/to/update_brew.sh

After adding the entry, save it and exit the editor.

Using a Launch Agent

Launch agents are another method used to schedule tasks on macOS. They offer more functionality and options than cron jobs. Here is how you can set up a launch agent to automate your Homebrew update script:

Step-by-Step Guide for Launch Agent Setup

1. Create a launch agent configuration file. You can do this in a text editor. Here's an example of what the file might contain:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
    <key>Label</key>
    <string>com.user.homebrewupdate</string>
    <key>ProgramArguments</key>
    <array>
        <string>/bin/bash</string>
        <string>/path/to/update_brew.sh</string>
    </array>
    <key>StartCalendarInterval</key>
    <dict>
        <key>Hour</key>
        <integer>2</integer>
        <key>Minute</key>
        <integer>0</integer>
    </dict>
</dict>
</plist>

Replace /path/to/update_brew.sh with the path to your script and save this plist file as com.user.homebrewupdate.plist in ~/Library/LaunchAgents/. If this directory doesn't exist, you may need to create it.

The above configuration tells macOS to run the script every day at 2 AM.

2. Load the launch agent using launchctl by running the following command in the terminal:

launchctl load ~/Library/LaunchAgents/com.user.homebrewupdate.plist

With this setup, the agent is now scheduled and will execute the script at the specified time.

Conclusion

By automating the Homebrew update process on macOS, you can ensure that all your packages stay up to date without manual intervention. This not only saves time but also enhances security and functionality by always running the latest version of software and tools.

This comprehensive guide has walked you through how to set up a shell script, make it executable, and use various automation methods to schedule it. Whether you choose a cron job or a launch agent, both options provide a reliable way to automate your updates.

Feel free to adjust the automation frequency to suit your specific needs, and continue exploring more advanced scripting and scheduling options if you want to add further customization to your setup.

With the automatic update process, your Homebrew-managed applications stay up to date, giving you more time to focus on your tasks and projects. Be happy!

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