Hidden Files and Folders
Open terminal and paste following codes to:
chflags hidden <file/folder>
Show Hidden files and folders
defaults write com.apple.finder AppleShowAllFiles YES; killall Finder
Hide Hidden files and folders
defaults write com.apple.finder AppleShowAllFiles NO; killall Finder
defaults write com.apple.screencapture location \User\...;
killall SystemUIServer
defaults write com.apple.PowerChime ChimeOnAllHardware -bool TRUE; open /System/Library/CoreServices/PowerChime.app &
defaults write com.apple.PowerChime ChimeOnAllHardware -bool FALSE; killall PowerChime
Terminal commands history that contained the word "killall"
history | grep killall
When .app becomes corrupt when its not really corrupt
sudo spctl --master-enable