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Full Discussion: perl : stdout is not return to screen
Top Forums Shell Programming and Scripting perl : stdout is not return to screen Post 302222022 by cbkihong on Tuesday 5th of August 2008 10:46:50 PM
Old 08-05-2008
So, Perl inherits the streams pointed to by STDIN, STDOUT and STDERR from the shell. If you need to re-connect them to other streams the way you did, you should first save a reference to the original filehandles in some variables beforehand, so that when you need to restore you can reinitialize them using these references saved. Otherwise, the streams are closed and you have no way to open them again until the end of your script.

Or, you can wrap the code needed to use custom STD* streams in a code block, and use "local" variable instead. This way, the original streams are just suppressed but not closed while in the code block, that will be restored when the local scope terminates.

I'll give you an example of the second approach because I think this is easier.

Code:
print "This will be printed to STDOUT\n";
{
    local *STDOUT;
    open(STDOUT, ">/dev/null") or die $!;
    print "This will be trashed to nowhere\n";
}
print "This will be printed to STDOUT\n";

 

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LEARN ABOUT DEBIAN

email::send::io

Email::Send::IO(3pm)					User Contributed Perl Documentation				      Email::Send::IO(3pm)

NAME

       Email::Send::IO - Send messages using IO operations

SYNOPSIS

	 use Email::Send;

	 my $mailer = Email::Send->new({mailer => 'IO'});

	 $mailer->send($message); # To STDERR

	 $mailer->mailer_args('filename.txt');
	 $mailer->send($message); # write file

DESCRIPTION

       This is a mailer for "Email::Send" that will send a message using IO operations. By default it sends mail to STDERR, very useful for debug-
       ging.  The IO functionality is built upon "IO::All". Any additional arguments passed to "send" will be used as arguments to "IO::All::io".

       You can globally change where IO is sent by modifying the @Email::Send::IO::IO package variable.

	 @Email::Send::IO::IO = ('-'); # always append to STDOUT.

       Examples

       Sending to STDOUT.

	 send IO => $message, '-';

       Send to a socket.

	 send IO => $message, 'server:1337';

SEE ALSO

       Email::Send, IO::All, perl.

AUTHOR

       Current maintainer: Ricardo SIGNES, <rjbs@cpan.org>.

       Original author: Casey West, <casey@geeknest.com>.

COPYRIGHT

	 Copyright (c) 2005 Casey West.  All rights reserved.
	 This module is free software; you can redistribute it and/or modify it
	 under the same terms as Perl itself.

perl v5.8.8							    2007-07-29						      Email::Send::IO(3pm)
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