CODEWITHSUNDEEP
linuxbash
Mark Galeck
Mark Galeck

Reputation: 6385

how to tell if my stdin is coming from stdout or stderr of the piped-in process

How to tell from Linux process2 whether I am given standard output or error from the previous process. Is it possible, to tell inside process2, whether particular line comes from stderr or stout

bash>process1 2>&1 | process2

So I guess by John's answer, it is "no". Then I am guessing, one way to handle this, is to inject specific prefixes for each line inside process1:

1: <line>

for stdout

2: <line>

for stderr

then I can inspect them in process2. Is this the normal thing to do?

Upvotes: 0

Views: 73

Answers (1)

John Zwinck
John Zwinck

Reputation: 249153

No, it is not possible. You can differentiate stdin from a terminal by isatty() but not what sort of stream the input came from in the way you want.

Upvotes: 2

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