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how do i redirect STDOUT, STDIN, or STDERR to a FILE?

( #11007=categorized question: print w/ replies, xml ) Need Help??
Contributed by Buckaroo Buddha on May 10, 2000 at 20:51 UTC
Q&A  > input and output


Description:

I wanted to do something like the following.
open( FILE, $file ); redirect( STDOUT, FILE );
Your mission: define sub redirect. :-)

Answer: how do i redirect STDOUT, STDIN, or STDERR to a FILE?
contributed by perlmonkey

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";
Answer: how do i redirect STDOUT, STDIN, or STDERR to a FILE?
contributed by plaid

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
Answer: how do i redirect STDOUT, STDIN, or STDERR to a FILE?
contributed by pwesthagen

Try this, worked for me:

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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