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Re: how do i redirect STDOUT, STDIN, or STDERR to a FILE?⭐
by perlmonkey (Hermit) on May 11, 2000 at 07:02 UTC
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The easist way to do this is to use fdopen from IO::Handle:
use IO::Handle;
open INPUT, '<', "input.txt" or die $!;
open OUTPUT, '>', "output.txt" or die $!;
open ERROR, '>', "error.txt" or die $!;
STDIN->fdopen( \*INPUT, 'r' ) or die $!;
STDOUT->fdopen( \*OUTPUT, 'w' ) or die $!;
STDERR->fdopen( \*ERROR, 'w' ) or die $!;
# prints to output.txt:
print "Hello Output File\n";
# reads everything from input.txt and prints it to output.txt:
print <>;
# prints to error.txt:
warn "Hello Error File\n";
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Re: how do i redirect STDOUT, STDIN, or STDERR to a FILE?⭐
by plaid (Chaplain) on May 10, 2000 at 21:17 UTC
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The typical way to do this would be in the way
you run it from the command line, e.g.
./script.pl < infile > outfile
This would take STDIN from infile and put STDOUT
to outfile. The sh type shells and csh type
shells have different ways to do STDERROR. Under
bash, you'd do something like
./script.pl < infile > outfile 2> errfile
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Re: how do i redirect STDOUT, STDIN, or STDERR to a FILE?
by graff (Chancellor) on Apr 05, 2002 at 04:26 UTC
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This works for me (I haven't tried it on Windoze,
but I wouldn't expect that to make a difference):
open( STDERR, ">", $stderrFileName );
and likewise for STDOUT.
For STDIN, you would replace ">" with "<".
Originally posted as a Categorized Answer. | [reply]
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Re: how do i redirect STDOUT, STDIN, or STDERR to a FILE?
by Buckaroo Buddha (Scribe) on May 10, 2000 at 23:15 UTC
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final self answer ... it works now
if ($opt_f eq '') {
print "Please enter the OUTPUT filename [defaults to scre
+en]: ";
$output_filename = <STDIN>;
chomp($output_filename);
if ($output_filename eq '') {
} else {
# open(SAVOUT, ">&STDOUT"); # save the stdout fhan
+dle
open(STDOUT,">" . $output_filename);
select(STDOUT); # force a flush on stdout so tha
+t any output will be in sync.
$| = 1;
}
} elsif ($opt_f ne "DEFAULT") {
$output_filename = $opt_f;
#open(SAVOUT, ">&STDOUT"); # save the stdout fhandle
open(STDOUT,">" . $output_filename);
select(STDOUT); # force a flush on stdout so that any ou
+tput will be in sync.
$| = 1;
}
maybe someone else will get some mileage out of this
i know i use perlmonks as a reference all the time
<g>
Originally posted as a Categorized Answer. | [reply]
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Re: how do i redirect STDOUT, STDIN, or STDERR to a FILE?
by Buckaroo Buddha (Scribe) on May 10, 2000 at 22:40 UTC
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but i'm trying to do it based on a user determined option
i'm writing this to be a standalone .EXE that people who don't
use PERL can run this one script ... thanks to 'perl2exe' this is
possible
if someone enters
myscript.exe -f filename.txt
i'd like to send it to a file
but i'd also like to be able to ask them
print "what output filename do you want?";
$outfilehandle = <STDIN>;
============================================
i just spoke to a friend of mine and have found
open(STDOUT, ">>$LOGGINGFILE"); # redirect them to the log file
i havent tested it yet but it looks about right
Originally posted as a Categorized Answer. | [reply]
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Re: how do i redirect STDOUT, STDIN, or STDERR to a FILE?
by pwesthagen (Initiate) on Apr 04, 2012 at 22:52 UTC
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open FILE, ">$file";
select FILE; # print will use FILE instead of STDOUT
print "Hello, world!"; # goes to FILE
select STDOUT; # back to normal
print "Goodbye."; # goes to STDOUT
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Re: how do i redirect STDOUT, STDIN, or STDERR to a FILE?
by scopey (Novice) on Jul 09, 2008 at 22:04 UTC
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I found this thread while looking for a way to redirect Data::Dumper output to a file. Using STDOUT as a filehandle can indeed do this:
print "Creating .\\ch9.log ...";
open STDOUT, ">ch9.log" or die $!;
print Dumper data_for_path ('.');
close STDOUT;
print "Done!\n";
This approach produces an error due to the final print statement (print() on closed filehandle STDOUT at...) Anybody know how I can get STDOUT to direct output back to the screen? | [reply]
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No need to open STDOUT in the first place - just selecting a file handle makes it the default target for a print operation:
open my $handle, '>', 'ch9.log' or die $!;
select $handle;
print Dumper(...);
close $handle;
select STDOUT;
print "Done!\n";
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Re: how do i redirect STDOUT, STDIN, or STDERR to a FILE?
by Mago (Parson) on Jul 11, 2003 at 15:17 UTC
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#!/usr/bin/perl
use strict;
use warnings;
my $opt_f = './output.txt';
if ($opt_f ne ''){
open(STDOUT, ">> $opt_f");
}
print "Start Arquive Mode\n";
print "Hello Perl Monks !\n";
print "End Arquive Mode\n";
Originally posted as a Categorized Answer. | [reply]
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Re: how do i redirect STDOUT, STDIN, or STDERR to a FILE?
by Buckaroo Buddha (Scribe) on May 10, 2000 at 22:55 UTC
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if ($opt_f eq '') {
print "Please enter the OUTPUT filename [defaults to screen]: ";
$output_filename = <STDIN>;
chomp($output_filename);
if ($output_filename eq '') {
} else {
open(SAVOUT, ">&STDOUT"); # save the stdout fhandle
open(STDOUT,">" . $output_filename);
select(STDOUT); # force a flush on stdout so that any output
+will be in sync.
$| = 1;
}
} elsif ($opt_f ne "DEFAULT") {
$output_filename = $opt_f;
}
unfortunately, it dosen't seem to work :(
Originally posted as a Categorized Answer. | [reply]
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Re: how do i redirect STDOUT, STDIN, or STDERR to a FILE?
by Anonymous Monk on Aug 04, 2003 at 21:09 UTC
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Re: how do i redirect STDOUT, STDIN, or STDERR to a FILE?
by Buckaroo Buddha (Scribe) on May 10, 2000 at 20:59 UTC
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