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I have a first perl-program ("first.pl") that calls a second perl-
program ("second.pl") and captures STDOUT and STDERR.
Is there a way inside "second.pl" to magically open a filehandle to
the terminal, even though STDOUT and STDERR are both redirected ?
I'm working under Ubuntu Linux.

first.pl
======
use strict;
use warnings;
system 'perl second.pl >file1.txt 2>file2.txt';

second.pl
======
use strict;
use warnings;
print STDOUT "This is STDOUT\n";
print STDERR "This is STDERR\n";
open my $fh, '>', ??magic-terminal?? or die "Error: Can't open magic
terminal because $!";
print {$fh} "This is magically going to terminal\n";
close $fh;

On Fri, 22 Jan 2010 09:31:46 -0800, Dilbert wrote:

> I have a first perl-program ("first.pl") that calls a second perl-
> program ("second.pl") and captures STDOUT and STDERR. Is there a way
> inside "second.pl" to magically open a filehandle to the terminal, even
> though STDOUT and STDERR are both redirected ? I'm working under Ubuntu
> Linux.
>
> first.pl
> ======
> use strict;
> use warnings;
> system 'perl second.pl >file1.txt 2>file2.txt';
>
> second.pl
> ======
> use strict;
> use warnings;
> print STDOUT "This is STDOUT\n";
> print STDERR "This is STDERR\n";
> open my $fh, '>', ??magic-terminal?? or die "Error: Can't open magic
> terminal because $!";
> print {$fh} "This is magically going to terminal\n"; close $fh;

open my$fh, ">", "/dev/tty" or die ...

M4

On 2010-01-22, Dilbert <> wrote:
> I have a first perl-program ("first.pl") that calls a second perl-
> program ("second.pl") and captures STDOUT and STDERR.
> Is there a way inside "second.pl" to magically open a filehandle to
> the terminal, even though STDOUT and STDERR are both redirected ?

perldoc Term::ReadLine;

> I'm working under Ubuntu Linux.

Does not matter...

Hope this helps,
Ilya

On Jan 22, 9:31*am, Dilbert <dilbert1...@gmail.com> wrote:
> I have a first perl-program ("first.pl") that calls a second perl-
> program ("second.pl") and captures STDOUT and STDERR.
> Is there a way inside "second.pl" to magically open a filehandle to
> the terminal, even though STDOUT and STDERR are both redirected ?
> I'm working under Ubuntu Linux.
>
> first.pl
> ======
> use strict;
> use warnings;
> system 'perl second.pl >file1.txt 2>file2.txt';
>
> second.pl
> ======
> use strict;
> use warnings;
> print STDOUT "This is STDOUT\n";
> print STDERR "This is STDERR\n";
> open my $fh, '>', ??magic-terminal?? or die "Error: Can't open magic
> terminal because $!";
> print {$fh} "This is magically going to terminal\n";
> close $fh;


A convoluted but more Unix-y portable option
is to dup STDOUT and undo the close-on-exec
flag before the system call and then pass
the dup'ed fd in:


first.pl
========
use strict;
use warnings;
use Fcntl qw/F_SETFD/;

open( SAVEOUT, ">&STDOUT" ) or die $!;
fcntl( SAVEOUT, F_SETFD, 0 )
or die "Can't clear close-on-exec flag on SAVEOUT",": $!";

system "perl second.pl " . fileno(SAVEOUT) . " "
. fileno(SAVEOUT) . " >&2"
. " >file1.txt 2>file2.txt";


second.txt
==========
use strict;
use warnings;

my $savefd = shift; # get STDOUT dup fd

print STDOUT "This is STDOUT\n";
print STDERR "This is STDERR\n";

open(SAVEOUT, "+<&=$savefd") or die "can't re-open SAVEOUT: $!";
print SAVEOUT "This is magically going to terminal\n";

--
Charles DeRykus

On Jan 22, 5:13*pm, Ben Morrow <b...@morrow.me.uk> wrote:
> Quoth "C.DeRykus" <dery...@gmail.com>:
>
>
> ...

>
> Since /dev/tty is one of only four files mentioned by name in POSIX,
> it's probably safe to rely on it being there .
>

<off-topic>

Suprisingly, I didn't find it when I was logged into FreeBSD.
which led me down the path of convolution. Of course, it's
a free FreeBSD shell account...maybe that's significant.

</off-topic>

--
Charles DeRykus

> On Jan 22, 9:31*am, Dilbert <dilbert1...@gmail.com> wrote:
> > Is there a way inside "second.pl" to magically open a filehandle to
> > the terminal, even though STDOUT and STDERR are both redirected ?
> > I'm working under Ubuntu Linux.

On 22 jan, 21:49, Martijn Lievaart <m...@rtij.nl.invlalid> wrote:
On 22 jan, 23:20, "Mumia W." <paduille.4061.mumia.w
+nos...@earthlink.net> wrote:
On 23 jan, 01:27, Ilya Zakharevich <nospam-ab...@ilyaz.org> wrote:
On 23 jan, 01:46, "C.DeRykus" <dery...@gmail.com> wrote:
On 23 jan, 02:13, Ben Morrow <b...@morrow.me.uk> wrote:

Thanks to everyone who replied, there are a lot of good suggestions I
can go through for my problem.