I noticed that coloured output stopped working a few months back. Took a bit of poking around. Wondered if the library might be checking isatty(). Found the code change. Also verified my use case by setting FORCE_COLOR=1.

What I had been doing for long output, mytool | less -R.

You will notice, from the perspective of mytool, isatty() gives different answers for stdin and stdout.

But, it's not that simple. Different tools and different code have diffrent needs. Sometimes it's best that the library do the result because it doesn't know the context.