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Full Discussion: multiple variables assignement (stdout/stderr outputs)
Top Forums UNIX for Dummies Questions & Answers multiple variables assignement (stdout/stderr outputs) Post 302447966 by agama on Tuesday 24th of August 2010 11:06:00 PM
Old 08-25-2010
Quote:
Originally Posted by anthalamus
I would like to assign the output of stdout to a variable and that of stderr to another one, and this without using temporary files/named pipes.
I agree with Corona688, cannot be done without pipes. However, you said 'named pipes' which technically are different beasts so I offer this "mess" for you to consider.

Code:
#!/usr/bin/env ksh 
(ls *.jpg bfoo | sed 's/^/STDOUT /') 2>&1 | awk ' 
        /STDOUT/ { 
                gsub( "STDOUT ", "" ); 
                o1 = o1 $0 "; "; 
                next;
        } 
        {
                o2 = o2 $0 "; ";
        } 
        END{ 
                printf( "%s~%s\n", o1, o2 ); 
        }' |  IFS="~" read  stdout stderr
echo "stdout=$stdout"
echo "stderr=$stderr"

It all can be crammed on one line; I've formatted it to be easier to read. It makes the assumption that the tilde (~) is never found in either the stdout or stderr stream. The records of each output stream are separated with semicolons, so if the output contains them, things will be difficult.

Running the script in my small test environment produced:
Code:
$ t20   
stdout=bar.jpg; foo.jpg; snapshot.jpg; 
stderr=ls: bfoo: not found;

I tested this in Kshell; I don't think it will work under bash as bash has issues executing a command and reading the output into variables. It will also be subject to the limits that Kshell might impose on variable value lengths or that awk might impose on string lengths. If you have a command that produces rather long output/error you could have problems.

Regardless, interesting brain twister.
This User Gave Thanks to agama For This Post:
anthalamus
 

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LEARN ABOUT DEBIAN

ompi-iof

OMPI-IOF(1)							     Open MPI							       OMPI-IOF(1)

NAME

       ompi-iof, orte-iof - Displays a copy of the output streams from a process.

       NOTE: ompi-iof, and orte-iof are exact synonyms for each other. Using any of the names will result in exactly identical behavior.

SYNOPSIS

       ompi-iof [ options ]

Options
       ompi-iof will display a copy of the indicated stdout, stderr, and/or stddiag streams from the designated process.

       -pid | --pid
		 The pid of the mpirun executing the process whose streams are to be copied

       -stdout | --stdout
		 Display a copy of the specified process' stdout. If no options are specified, this will act as the default

       -stderr | --stderr
		 Display a copy of the specified process' stderr.

       -stddiag | --stddiag
		 Display a copy of the specified process' stddiag.

       -rank | --rank
		 The rank of the process whose output is to be copied.

DESCRIPTION

       ompi-iof  displays  a copy of the indicated stdout, stderr, and/or stddiag streams from the designated process. At this time, a ctrl-C must
       be used to terminate the program.  The program will terminate cleanly, telling the associated mpirun to close the requested streams  before
       exiting.

SEE ALSO

       orterun(1)

1.4.5								   Feb 10, 2012 						       OMPI-IOF(1)
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