How to pipe app1 to app2, but show both output in terminal?

Question

I would like to know how can I redirect the stdout of an app to an input of an another app but still see the app1 output.

The source app is written in c, the second app is in perl. The purpose of this, that i would like to interpret the output of the C program with the perl script, and do something based on the input. The problem is if i use the ./c_app | ./perl.pl, so use the | pipe, i can only see the output of the perl script. It's like the perl would swallow the output of the C_app.

I've tried to use the tee, and found some examples, but all of them are based on redirecting the output of the source app to a file, not to an input of an other application.

The below figure illustrate the process, the got and the expected result.

A limitation would be that I cannot modify the C app, nor the perl, so i would solve it by using linux stuffs. Is it possible to use the same terminal to see both output? I have no idea how to solve it.

Any recommendation, bash script, etc. would be appreciated.

Possibly related: using stdout twice (but not tee as I know it) — steeldriver, Jun 27 '19 at 11:19
https://unix.stackexchange.com/questions/28503/how-can-i-send-stdout-to-multiple-commands . In most shells, run app1 | tee >(app2) . — Mark Plotnick, Jun 27 '19 at 11:22
Also: https://unix.stackexchange.com/questions/178752/using-tee-to-output-intermediate-results-to-stdout-instead-of-files https://unix.stackexchange.com/questions/273118/direct-output-to-pipe-and-stdout — muru, Jun 27 '19 at 11:35

score 3 · Answer 1 · edited Jun 27 '19 at 11:35

3

Thanks @steeldriver the recommendation!

The solution is:

./c_app | tee /dev/tty | perl server.pl

edited Jun 27 '19 at 11:35

muru

72,889

answered Jun 27 '19 at 11:33

iddqd

41

Yes, tee is a "T-shaped" pipe – glenn jackman Jun 27 '19 at 13:31

How to pipe app1 to app2, but show both output in terminal?

1 Answers1