?
Solved

Capturing STDERR Output

Posted on 1999-01-21
2
Medium Priority
?
694 Views
Last Modified: 2008-03-10
I have a process that return text using STDERR.
I need to run something like:
@out=`process command`;
To get the output, but this gets only STDOUT.
How can I get the STDERR like that in an Easy way?
0
Comment
Question by:eofek
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
2 Comments
 
LVL 5

Expert Comment

by:thoellri
ID: 1210227
From "perldoc perlfaq8" :

     With any of these, you can change file descriptors before
     the call:

         open(STDOUT, ">logfile");
         system("ls");

     or you can use Bourne shell file-descriptor redirection:

         $output = `$cmd 2>some_file`;
         open (PIPE, "cmd 2>some_file |");

     You can also use file-descriptor redirection to make STDERR
     a duplicate of STDOUT:

         $output = `$cmd 2>&1`;
         open (PIPE, "cmd 2>&1 |");

Hope this helps
   Tobias

0
 

Accepted Solution

by:
meyoz earned 100 total points
ID: 1210228
Use this (I've checked it myself - it's working):

$pipename="pipename";
system("mkfifo -m 600 $pipename"); || die("Cannot make fifo: $!\n");
if (!fork()) {
  close(STDOUT);
  open(STDOUT,">$pipename");
  close(STDERR);
  open(STDERR,">$pipename");
  system("cmd"); # place your command here
  exit(0);
} else {
  open(CATCH,"<$pipename");
# now you have STD(OUT,ERR) of cmd in CATCH
# or you can do so:
#  @out=`cat $pipename`
}
unlink("$pipename");

You will get mixed STDOUT and STDERR
I think it's clear how to capture STDOUT and STDERR separately :)

0

Featured Post

VIDEO: THE CONCERTO CLOUD FOR HEALTHCARE

Modern healthcare requires a modern cloud. View this brief video to understand how the Concerto Cloud for Healthcare can help your organization.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

A year or so back I was asked to have a play with MongoDB; within half an hour I had downloaded (http://www.mongodb.org/downloads),  installed and started the daemon, and had a console window open. After an hour or two of playing at the command …
There are many situations when we need to display the data in sorted order. For example: Student details by name or by rank or by total marks etc. If you are working on data driven based projects then you will use sorting techniques very frequently.…
Explain concepts important to validation of email addresses with regular expressions. Applies to most languages/tools that uses regular expressions. Consider email address RFCs: Look at HTML5 form input element (with type=email) regex pattern: T…
Six Sigma Control Plans

777 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question