Time Machine for Developers

The problem

Time Machine will backup your files. For a developer, and having loads of node_modules and vendor directories for projects, this is huge time suck and waste since those can be brought back with npm, yarn, composer, etc.

The solution

Directories can be excluded from Time Machine using the cli.

Adding exclusions

First, verify that you can get a list of directories that you want to exclude:

cd "$HOME/code" && find $(pwd) \
    -maxdepth 3 \
    -type d \( -name vendor -o -name node_modules \)

The first part of the above assumes you keep your code in a code directory in your home directory. You'll need to change that if that's not the case for you.

Executing this command should output a list of directories that have vendor or node_modules directories. These are what you want excluded from Time Machine.

Next, we can add to the above command to pipe those into the Time Machine utility tool, tmutil, to be excluded.

cd "$HOME/code" && find $(pwd) \
    -maxdepth 3 \
    -type d \( -name vendor -o -name node_modules \) \
    -prune \
    -exec tmutil addexclusion {} \; \
    -exec tmutil isexcluded {} \;

Viewing exclusions

You can see all excluded files/directories with the following command:

sudo mdfind "com_apple_backup_excludeItem = 'com.apple.backupd'"

You can see if a specific file or directory is excluded with:

tmutil isexcluded /some/file/path.txt

Verify that directories we excluded earlier are in fact exluded:

cd "$HOME/code" && find $(pwd) \
  -maxdepth 3 \
  -type d \( -name vendor -o -name node_modules \) \
  -exec tmutil isexcluded {} + | grep -F "[Excluded]"

Remove exclusions

Or remove all the exclusions we added

cd "$HOME/code" && find $(pwd) \
  -maxdepth 3 \
  -type d \( -name vendor -o -name node_modules \) \
  -prune \
  -exec tmutil removeexclusion {} \; \
  -exec tmutil isexcluded {} \;

Automate

We can automate this so if we create a new project we don't have to worry about manually adding the exclusion with a cron job.

Create a bash file that will run the addexclusion commands:

#!/usr/bin/env bash

cd "$HOME/code" && find $(pwd) \
  -maxdepth 3 \
  -type d \( -name vendor -o -name node_modules \) \
  -prune \
  -exec tmutil addexclusion {} \; \
  -exec tmutil isexcluded {} \;

Remember to change the $HOME/code to wherever you keep your projects. I put this at $HOME/code/machine-utils/time-machine-exclusions.sh.

Make sure it's executuble:

chmod +x $HOME/code/machine-utils/time-machine-exclusions.sh

Add this as a cronjob to run every hour:

• crontab -e
• press i to go into "insert" mode
• paste the following line (Change according to where you saved the file on your machine. The full path is required.):
  • 0 * * * * /Users/davidadams/code/machine-utils/time-machine-exclusions.sh
• press esc to exit "insert" mode
• type :x to save and exit