Auto-updating Homebrew

Question

i'm currently using the Homebrew package manager and my question is: is possibile to write a bash's script in order to execute brew update and eventually brew upgrade whenever opening a shell for the first time? I'm using iTerm at the moment.

Answer 1

This was easily done with scripts and now the built-in autoupdate mechanism handles this elegantly. See Tate’s excellent answer for details

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If the automatic update and upgrade aren’t working, here is another way for older versions.

For efficiency (and cool factor), I would use a tool like Lingon to launch this script periodically using launchctl/launchd instead of each time you start a shell. On my MacBook, it takes 3 seconds to update the second time (no work done, DNS cache set, etc...) and it take 10 second to run the first time (no work done) or 15+ seconds if a package needs to be downloaded or compiled.

Perhaps once a day or once an hour - running in the background would be sufficient given those times to execute?

You could make a simple script /usr/local/bin/brewup that calls brew in turn and logs the results to the system log. If you don’t like chasing logs in the centralized log store, “teeing” them to a text file works well, too.

#!/bin/bash

brew=/usr/local/bin/brew
logger=/usr/bin/logger

$brew update 2>&1  | $logger -t brewup.update
$brew upgrade 2>&1 | $logger -t brewup.upgrade
$brew cleanup 2>&1 | $logger -t brewup.cleanup

I just call the brewup when I'm about to go make tea or when I get started and let it run in the background.

brewup &

Answer 2

Homebrew has an autoupdate subcommand. So you can run:

brew autoupdate start

To automatically run brew update every 24 hours. The docs linked above outline a number of configuration options. Because you'd like to also run brew upgrade, you can run:

brew autoupdate start --upgrade

Under the hood brew autoupdate is using launchd.

05/2024 Update: As of March 2024, autoupdate is no longer an official homebrew tap, this means you'll need to run brew tap DomT4/homebrew-autoupdate for this functionality.

Answer 3

There is a tool called homebrew-autoupdate which will do this for you. It can automatically run brew update in the background every 24 hours (configurable) to ensure that you always have fresh homebrew data when you go to install/upgrade packages.

To install it run brew tap domt4/autoupdate and brew autoupdate --start 43200 to configure it to autoupdate every 12 hours (43200 seconds).

EDIT: This is now integrated into Homebrew, see https://github.com/Homebrew/homebrew-autoupdate.

Answer 4

You might want to ask yourself: "Do I really want to auto-update applications, which the applications that I build myself depend upon?"

Brew team turned down this feature request to facilitate early updates.

My interpretation of their reasoning: "The risk of malicious code slipping through the opensource auditing process weighs more than the incidental need for a speedy update."

If this is your line of reasoning, you like to be in control of software updates, and you care a lot about homebrew packages being up-to-date, you are probably better off adding a line to the bottom of .bashrc (or the rc file of your favorite shell) asking:

brew outdated

This will confront you, in every new terminal, with the outdated packages. When your annoyance reaches the limit (you feel ready to update), you'll be happy to do the necessary.

Answer 5

I prefer to update Homebrew on startup. I have a script Update Homebrew.sh in ~/Library/Scripts:

#!/usr/local/bin/bash
    
brew update
brew upgrade
brew cleanup -s

Don't forget to make the script executable using chmod u+x.

The script is launched on startup using launchd. For that, I have Update Homebrew.plist in ~/Library/LaunchAgents:

<?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>Update Homebrew</string>
        <key>ProgramArguments</key>
        <array>
            <string>/Users/[home]/Library/Scripts/Update Homebrew.sh</string>
        </array>
        <key>RunAtLoad</key>
        <true/>
    </dict>
</plist>

Where [home] is the name of your home folder. (You can't use the tilde in this file.)

Answer 6

You can use cron to simplify this.

Find your brew installation location with which brew. Mine was in the default location:

/usr/local/bin/brew

Using crontab -e add this line to the editor (update with your brew location):

0 9 * * * /usr/local/bin/brew update && /usr/local/bin/brew upgrade && /usr/local/bin/brew cleanup

The above will update brew, upgrade formulae and casks, and then clean up - every morning at 9am.