Some of these Mac settings are just shortcuts — you can enable them in the usual way, using the mouse. But Terminal makes things simple. Instead of opening the System Preferences app, then finding (or remembering) a setting you want to change, and then searching further until you actually find the right checkbox, you can just type (or paste) a command, then hit return.
Most of these are secret settings, though. They are impossible to change without Terminal. Let’s check them out.
First things first. Terminal provides a text-based interface to your Mac. Instead of clicking buttons and dragging, you just type instructions for the computer into a text field. If you’re not familiar with this powerful, built-in tool, you should read our post on basic Mac Terminal tricks.
How to use these secret Mac settings
Once you know how to use Terminal, you can use it for many Mac tasks. To change any of the secret Mac settings we mentioned, you can just paste a line of code into the Terminal window and hit Enter. The changes will take effect instantly, with no feedback. You’ll just have to test things to see the results. In most cases, the last word in the command is “true.” To reverse the change, just replace “true” with “false.”1
Other commands offer several options. For instance, the command to pick the image type for screenshots looks like this:
defaults write com.apple.screencapture type -string "png"
To choose a different image format, replace png with one of the following image
suffixes: bmp, gif, jpg, pdf, tiff. Remember to keep the quotes.
Now, here are a bunch of useful settings. You can find all these, and a lot more, on this Github page, maintained by Mathias Bynens.
All commands are copied from the Github page. I have added comments to the less obvious ones.
Expand save panel by default
This one means you’ll never have to expans the save panel manually ever again.
defaults write NSGlobalDomain NSNavPanelExpandedStateForSaveMode -bool true
defaults write NSGlobalDomain NSNavPanelExpandedStateForSaveMode2 -bool true
Disable automatic termination of inactive apps
MacOS quits apps that you haven’t used in a while, in order to conserve memory and battery power — just like iOS. This setting disables this feature.
defaults write NSGlobalDomain NSDisableAutomaticTermination -bool true
Disable Notification Center and remove the menu bar icon
Beautiful, baby. Keep a nice clean menubar.
launchctl unload -w /System/Library/LaunchAgents/com.apple.notificationcenterui.plist 2> /dev/null
Read more at cultofmac.com