Detect if stdin is a tty device (terminal) or pipe in PHP?

Question

I wrote a php script. I want it show help message when called with standard input connected to a tty device (terminal) before reading and executing interactively, but dont show

Answer 1

Since PHP 7.2 you can use stream_isatty, which works on Windows too.

For example:

php -r "var_dump(stream_isatty(STDERR));"

Results in

bool(true)

But

php -r "var_dump(stream_isatty(STDERR));" 2>output.txt

Results in

bool(false)

(this of course works on STDOUT too).