Re: redirecting STDERR with IO::Tee
Date sent: Mon, 22 Jun 2009 10:53:06 -0700
From: pa...@compugenic.com
To: beginners@perl.org
Subject:redirecting STDERR with IO::Tee
I have a script which runs mostly via a cron job and sometimes
interactively. I would like STDERR to automatically print to both the
console and to a logfile simultaneously.
Right now I've gotten as far as merging both file handles with IO::Tee
but I'm not sure if I'm heading down the right path.
my $merged_stderr = IO::Tee-new( \*STDERR, new IO::File($errlog) );
This only works when explicitely naming the file handle in a print
statement. How can I take it to the next step, which is to have
STDERR automatically print to that file handle?
#!perl
use strict;
use IO::Tee;
warn Before the change;
open my $oldSTDERR, 'STDERR' or die;
close STDERR;
open my $DBG, '', 'debug.log' or die;
*STDERR = IO::Tee-new( $oldSTDERR, $DBG) or die;
warn after the change;
print to STDOUT\n;
print STDERR to STDERR\n;
system ('dir sdf_sgerdfwerg');
die Bleargh;
__END__
it's not possible to tee (this way) the STDERR of the child
processes, the best you can do is to decide whether you want them to
go to the file or the ordinary error output. Try to escape the close
STDERR;.
HTH, Jenda
= je...@krynicky.cz === http://Jenda.Krynicky.cz =
When it comes to wine, women and song, wizards are allowed
to get drunk and croon as much as they like.
-- Terry Pratchett in Sourcery
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Re: redirecting STDERR with IO::Tee
2009/6/23 pa...@compugenic.com:
I have a script which runs mostly via a cron job and sometimes interactively.
I would like STDERR to automatically print to both the console and to a
logfile simultaneously.
Right now I've gotten as far as merging both file handles with IO::Tee but
I'm not sure if I'm heading down the right path.
my $merged_stderr = IO::Tee-new( \*STDERR, new IO::File($errlog) );
This only works when explicitely naming the file handle in a print statement.
How can I take it to the next step, which is to have STDERR automatically
print to that file handle?
Hi,
What causes writting of STDERR?
If it's due to die and warn, you could redirect them to the customized routines.
Something like:
$SIG{__DIE__}=\log_die;
$SIG{__WARN__}=\log_warn;
sub log_die
{
my $time=scalar localtime;
open (HDW,,$err_log);
my $old=select HDW;$|=1;select $old;
print HDW $time, ,@_;
close HDW;
die @_;
}
sub log_warn
{
my $time=scalar localtime;
open (HDW,,$err_log);
my $old=select HDW;$|=1;select $old;
print HDW $time, ,@_;
close HDW;
}
--
In this magical land, everywhere
is in full bloom with flowers of evil.
- Jeff Pang (CN)
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Re: redirecting STDERR with IO::Tee
On Wed, Jun 24, 2009 at 05:52:36PM +0800, Jeff Pang wrote:
2009/6/23 pa...@compugenic.com:
I have a script which runs mostly via a cron job and sometimes
interactively. I would like STDERR to automatically print to both the
console and to a logfile simultaneously.
snip
Hi,
What causes writting of STDERR?
If it's due to die and warn, you could redirect them to the customized
routines.
Something like:
$SIG{__DIE__}=\log_die;
$SIG{__WARN__}=\log_warn;
snip
I would but this doesn't properly redirect other errors or warnings as
with system(). I actually created a new post due to lack of response to
this one, the new post is How to print errors to both STDERR a
file?.
Basically I think if this was STDOUT, I'd use IO::Tee to merge STDOUT
a log file and use the new filehandle in a 'select' statement to set it
as the default. But because this is STDERR I am not sure if this is
possible with Perl.
My goal is to learn something new about Perl and do this the right way,
as this task will be quite common for me. There are a lot of script I
run via cron jobs which I periodically run manually on the console.
Any suggestions would be appreciated.
Pablo
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RE: Redirecting STDERR
It partly depends on your operating system, I think. That's fine on Windows, but on UNIX I think that under some if not all circumstances your change will persist after the script finishes executing. I've never had to do it, but I've seen one method that goes like this: open(OLD_STDERR,STDERR) or die Failed to save STDERR; open(STDERR,script.err) or die Failed to redirect STDERR; do something... open(STDERR,OLD_STDERR) or die Failed to restore STDERR; -Original Message- From: Ryan Frantz [mailto:[EMAIL PROTECTED] Sent: Friday, October 07, 2005 12:10 PM To: beginners@perl.org Subject: Redirecting STDERR Perlers, I have a script where I redirect STDERR to a file so that I can capture 'die' messages like so: use warnings; use strict; my $logfile = /some/path/logfile.txt; open STDERR, $logfile; something or die Unable to do something()\n; close STDERR; Is it kosher to do this? Or is there a more preferred method to redirect 'die' messages? -- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] http://learn.perl.org/ http://learn.perl.org/first-response
Re: Redirecting STDERR
hi,
maybe u should redefined the __DIE__ handle for the reason of safety.
such as:
$SIG{__DIE__}=\log_die;
sub log_die
{
open (HDW,,$err_log);
select HDW;$|=1;select STDOUT;
print HDW @_;
close HDW;
die @_;
}
2005/10/8, Timothy Johnson [EMAIL PROTECTED]:
It partly depends on your operating system, I think. That's fine on
Windows, but on UNIX I think that under some if not all circumstances
your change will persist after the script finishes executing. I've
never had to do it, but I've seen one method that goes like this:
open(OLD_STDERR,STDERR) or die Failed to save STDERR;
open(STDERR,script.err) or die Failed to redirect STDERR;
do something...
open(STDERR,OLD_STDERR) or die Failed to restore STDERR;
-Original Message-
From: Ryan Frantz [mailto:[EMAIL PROTECTED]
Sent: Friday, October 07, 2005 12:10 PM
To: beginners@perl.org
Subject: Redirecting STDERR
Perlers,
I have a script where I redirect STDERR to a file so that I can capture
'die' messages like so:
use warnings;
use strict;
my $logfile = /some/path/logfile.txt;
open STDERR, $logfile;
something or die Unable to do something()\n;
close STDERR;
Is it kosher to do this? Or is there a more preferred method to
redirect 'die' messages?
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Re: Redirecting STDERR
Opening the filehandle STDERR to a file will not persist beyond termination of the script, nor will it affect other programs running at the same time as the script. It affects only the running script. STDERR of the shell is different from that of perl. On Friday 07 October 2005 16:56, Timothy Johnson wrote: It partly depends on your operating system, I think. That's fine on Windows, but on UNIX I think that under some if not all circumstances your change will persist after the script finishes executing. I've never had to do it, but I've seen one method that goes like this: open(OLD_STDERR,STDERR) or die Failed to save STDERR; open(STDERR,script.err) or die Failed to redirect STDERR; do something... open(STDERR,OLD_STDERR) or die Failed to restore STDERR; -Original Message- From: Ryan Frantz [mailto:[EMAIL PROTECTED] Sent: Friday, October 07, 2005 12:10 PM To: beginners@perl.org Subject: Redirecting STDERR Perlers, I have a script where I redirect STDERR to a file so that I can capture 'die' messages like so: use warnings; use strict; my $logfile = /some/path/logfile.txt; open STDERR, $logfile; something or die Unable to do something()\n; close STDERR; Is it kosher to do this? Or is there a more preferred method to redirect 'die' messages? -- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] http://learn.perl.org/ http://learn.perl.org/first-response
RE: Redirecting STDERR to 2 locations simultaneously
Try the Module IO::Tee, I haven't used it, but it's description sounds to be what you need -Original Message- From: Peter Scott [mailto:[EMAIL PROTECTED]] Sent: 13 November 2001 07:01 To: [EMAIL PROTECTED] Subject: Re: Redirecting STDERR to 2 locations simultaneously I have been trying to figure out if it possible to redirect STDERR to 2 locations at once. Specifically, I want certain errors to be redirected to both STDOUT and a log file. I have been unable to do this, and am not even sure it is possible. Redirecting to one or the other is now problem, but a solution that allows me to redirect to both simultaneously remains elusive. Any thoughts or suggestions would be appreciated. Thanks If you're on Unix, look up the 'tee' command. -- Peter Scott Pacific Systems Design Technologies http://www.perldebugged.com -- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] -- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
Re: Redirecting STDERR to 2 locations simultaneously
I have been trying to figure out if it possible to redirect STDERR to 2 locations at once. Specifically, I want certain errors to be redirected to both STDOUT and a log file. I have been unable to do this, and am not even sure it is possible. Redirecting to one or the other is now problem, but a solution that allows me to redirect to both simultaneously remains elusive. Any thoughts or suggestions would be appreciated. Thanks If you're on Unix, look up the 'tee' command. -- Peter Scott Pacific Systems Design Technologies http://www.perldebugged.com -- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
