This is a small Objective-C program that reports the current sleeping/awake status of the screen or locked/unlocked status of the login session. It's self-contained Universal Binary that runs on Apple Silicon and Intel-based Macs.

It requires a single argument (-s/--sleep, or -l/--lock) to select which detail to query. The program does not produce any output, instead it returns an exit code to indicate the status. This makes it well-suited for integration with shell scripts.

The meaning of the exit codes are as follows:

1. Download the latest release
2. Unzip dstat.zip and copy the dstat program to a directory in your $PATH — if you're unsure, /usr/local/bin is a solid choice.
3. Execute dstat <arg> from your shell or scripting environment (bash, zsh, etc)

Show help:

dstat -h

Example #1

dstat --lock 2>/dev/null
case $? in
  0) echo "screen is locked";;
  1) echo "screen is unlocked";;
  *) echo "something went pear shaped";;
esac

Example #2

dstat -l && echo "screen is locked"

Example #3

if dstat --sleep; then
  # display is sleeping
  say "time for bed"
fi

The tool uses APIs that interact with the active login session. Thus, it cannot function if there's nobody logged in to the system. An error code of 4 is returned in that scenario, so it can at least be detected by your script. If anyone knows of a way to query for the sleep status of the display while in a logged out state, please file a PR! 🙏

Please report any bugs or issues you encounter. This idea was inspired by this AskDifferent post, and is a somewhat more efficient followup to an earlier solution I came up with: display-is-sleeping.