All too often, I encounter a crucial but badly designed program that "breaks the output". It doesn't actually return its output to PHP's functions that execute the terminal command, but "force-output" it on the command line, separate from the returned data (which is empty).

For example, pdftotext.exe -v results in empty return data, but this text (which should be its return data) is outputted:

pdftotext version 4.03 [www.xpdfreader.com]
Copyright 1996-2021 Glyph & Cog, LLC

Doesn't matter if you use the -q option.

How to force software like this to not "separate-output" what should be its return data? And why/how do they even do this in the first place? I don't get how it's technically possible.

Code example:

var_dump(shell_exec('"C:\Program Files\xpdf-tools-win-4.03\bin64\pdftotext.exe" -v'));

Output:

pdftotext version 4.03 [www.xpdfreader.com]
Copyright 1996-2021 Glyph & Cog, LLC
NULL