Capture stdout (likely) with BSD grep

Question

I am trying to extract the version of fortran compiler using ifort -v command and then grep it check for version.

However this does not work.

%ifort -v
ifort version 16.0.1
%ifort -v | grep "version"
ifort version 16.0.1
%ifort -v | grep "xyz"
ifort version 16.0.1

It appears as if the output is getting printed irrespective of my pattern. So to test it out I tried the following redirection to null and it still printed. It seems likes the output is not going to the stdout.

%ifort -v > /dev/null
ifort version 16.0.1


%ifort -v 2>/dev/null
ifort: error #10236: file not found: '2'
ifort version 16.0.1

Is it possible that the information i see in shell is actually being written by a different process than the current executing ifort command and thats the reason I am unable to capture it? How can I capture this and grep it?

Edited to include redirecting the stderr. Seems like ifort has a different way of executing commands. — ashish g, Jan 21 '16 at 18:56
I am on tcsh shell however in bash ifort -v 2> /dev/null returns empty — ashish g, Jan 21 '16 at 19:03
In that case ifort writes to stderr. I do not know tcs but on bash you would simple do ifort -v 2>&1 | awk '{ print $2}' for example. — Michal, Jan 21 '16 at 19:11

score 0 · Answer 1 · edited May 23 '17 at 12:07

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Apparently the ifort -v writes to stderr. On bash redirecting stderr to stdout helps with that. The version could be obtained then for example using ifort -v 2>&1 | awk '{ print $2}'.

It looks like it is not trivial to redirect stderr to stdout on (t)csh and that csh family of shells is not well suited for scripting.

edited May 23 '17 at 12:07

Community

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answered Jan 21 '16 at 19:26

Michal

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`ifort -v |& ...` may well be preferable. – francescalus Jan 21 '16 at 19:37

Capture stdout (likely) with BSD grep

1 Answers1