OS X defaults
posted Mon 23 Apr 2012 by Michael Galloy under Macmathiasbynens has a great github repo of OS X commands to change various system defaults. Some of my favorites:
# Disable menu bar transparency
defaults write NSGlobalDomain AppleEnableMenuBarTransparency -bool false
# Disable the warning when changing a file extension
defaults write com.apple.finder FXEnableExtensionChangeWarning -bool false
# Show the ~/Library folder
chflags nohidden ~/Library
This is like a nerdy command line version of Secrets.