Veja a opção idle
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idle [timeout [cmd args]]
Sets a command that is run after the specified number of seconds inac‐ tivity is reached. This command will normally be the "blanker" command to create a screen blanker, but it can be any screen command. If no command is specified, only the timeout is set. A timeout of zero (ot the special timeout off) disables the timer. If no arguments are given, the current settings are displayed.