macOS 10.14.6, TeXstudio 2.12.16 (git 2.12.16)
The following script should result in an inforamation dialog that contains the word "test" but instead presents an empty dialog:
%SCRIPT
var proc = system("echo test")
proc.waitForFinished()
information(proc.readAllStandardOutputStr())
If you run echo test > out.txt in Terminal, however, a file out.txt will be produced containing the word test as it should.
If the second line is replaced with var proc = system("touch test","/Users/Haiiro") (with /Users/Haiiro replaced with the path to your user home folder) , you will see a file called test in your user home folder as expected.
The problem appears to be that proc.readAllStandardOutputStr() is returning an empty string instead of the stdout . Likewise, proc.readAllStandardErrorStr() returns an empty string.
As a workaound, I tried simply redirectly stdout to a file inside the system() call, but the file is not produced.