How do I redirect stdout & error to 2 separate files?

Question

I know how to redirect stdout & stderr to one file:

my_command_to_start_server &> app.log

but how can I redirect the stdout & stderror to 2 files?

In essence I want to duplicate what's getting written to my app.log to my health.log

Do you mean you want stdout to go to one file and stderr to a different file? Or do you mean you want both stdout and stderr to go to both `fileA` and also`fileB`? — Mark Setchell, Jul 04 '22 at 17:47
@MarkSetchell - I want both stdout and stderr to be written to `fileA` and `fileB` — Clifford Fajardo, Jul 17 '22 at 04:35

score 1 · Answer 1 · answered Jul 04 '22 at 17:22

Use tee.

my_command_to_start_server 2>&1 | tee app.log health.log > /dev/null

2>&1 makes standard error whatever standard output already is, effectively "merging" them. (&> ... is a shortcut for > ... 2> ..., which doesn't allow for the use of a pipe.) Then you pipe the merged stream to tee, which writes its standard input to both named files.

tee also writes to its own standard output, which we redirect to /dev/null instead of picking an arbitrary file to redirect standard output to with something like

... | tee health.log > app.log

How do I redirect stdout & error to 2 separate files?

1 Answers1