By default, macOS goes to sleep if it hasn't been used for a certain amount of time. However, there are cases we want to prevent it from happening such as during a presentation, downloading a big file.
macOS provides a command to do that:
Pressing ctrl + C will bring it back to the normal mode.
The command also supports the time parameter. It indicates that macOS won't enter the sleep mode after a given number of seconds.
For example, the command below asks macOS to awake in the next 10 minutes.
$ caffeinate -u -t 600