stra.py arg [...] annotates the output of running arg... with the name of the corresponding stream.
It works under either python 2 or 3.
pip install stra
./stra.py ls -l
[OUT] total 64
[OUT] -rw-r--r--@ 1 tcf staff 1487 Sep 2 21:32 LICENSE
[OUT] -rw-r--r-- 1 tcf staff 177 Sep 2 21:34 README.md
[OUT] -rwxr-xr-x 1 tcf staff 1731 Sep 2 21:23 stra.py