This tweak controls whether the full path will be shown in the Finder title bar.
Start a new Terminal session (in Finder click Applications > Utilities > Terminal).
To enable this setting, type (or copy and paste) the following command:
defaults write com.apple.finder _FXShowPosixPathInTitle -boolean true
To reset this setting to the default value, type (or copy and paste) the following command:
defaults delete com.apple.finder _FXShowPosixPathInTitle
To activate this tweak immediately, type the following command, or wait until the next reboot:
killall Finder
Close the Terminal session by typing exit at the prompt.
Disclaimer: Making any changes to your system can cause serious problems that may require you to reinstall your operating system. We cannot guarantee that problems resulting from these modifications can be resolved. Please follow the instructions carefully and use the information provided at your own risk.