Five months ago, I wrote a little command tool, blowhole, which allowed any Mac user running macOS Sierra to write to Sierra’s new unified log. The snag with it was that it could only write integers, because of a bug in the system call which was supposed to allow it to write arbitrary text.

It now transpires, thanks to information provided by Eddy Wong and Volodymyr Gorlov, that Apple was informed of this bug back in October 2016, and that Volodymyr Gorlov discovered a workaround, to which Eddy Wong kindly drew my attention (it was buried away in the original bug report).

I have now incorporated this into a completely rewritten version 2 of blowhole, which is available from Downloads above.

For example, if you just want to write the text Why doesn’t Apple fix its bugs? to Sierra’s unified log, all you have to call is
/usr/local/bin/blowhole -s "Why doesn't Apple fix its bugs?"

This is very easy from scripting languages such as AppleScript, and many apps including Eastgate’s Storyspace and Tinderbox. If you can call a command tool and pass it simple parameters such as the above, you can now use blowhole to record whatever you want in Sierra’s log.

The Zip archive provided includes simple documentation, a regular Mac installer package which is properly signed to install blowhole in /usr/local/bin, and an example property list to write a message as a Launch Agent. blowhole is completely free, and freely distributable.

I hope that this proves useful to you.