Show Hidden Files in Mac Finder by Default

Show Finder the light.

A one-time thing #

1. Press Command - Shift - . to toggle hidden files when in Finder

Make it permanent #

1. Set the default

    defaults write com.apple.finder AppleShowAllFiles YES
   

2. Confirm that the default is set

    defaults read com.apple.finder AppleShowAllFiles
   

3. Hold Option key, right-click Finder, then click Relaunch to pick up the new default

Revert it #

1. In the write command above, replace YES with NO

    defaults write com.apple.finder AppleShowAllFiles NO