If you Once your Mac is turned on, because an application is processing data or you are moving or copying files to an external storage device, it can be very annoying to first wake up the screen to read the progress. To prevent the display brightness from being reduced, you have two options. Either you use the free app Caffeine and use its simple user interface or you take the matter into your own hands and steer with a command in the terminal app.
This way the display brightness is no longer reduced
The terminal app is an extremely powerful tool for on-boarding. It helps to display hidden system files, has a calendar built in, can turn off shadow screenshots, and can even speed up the backup process for Time Machine backups. Likewise, it may prevent the display from falling asleep:
Open the Terminal App. It is located in the Applications> Utilities folder. Enter the command "caffeinate" (without quotation marks) into the app and press the Enter key. You are already in Caffeinate mode.
Note : If Caffeinate is active, your Mac will not hibernate, display brightness will not be dimmed, and the screen saver will not be activated.
Um To exit the mode, press the control key (crtl) + (c) while the terminal app is open.
Hint : You can also end the caffeinate mode time-controlled , All you have to do is attach to the command "caffeinate" "-t [Zeit in Sekunden]". Example: If you want the caffeinate mode to remain active for three hours or 10,800 seconds, you must enter the following into the terminal app: "coffeinate -t 10800" (without quotation marks).