in reply to top and STDERR hell...

Try IPC::Open3: 
#!/usr/bin/perl
use warnings;
use strict;
use IPC::Open3;
use IO::Select;

my $pid = $$;

my $pid1 = open3(0, \*READ,\*ERROR,"top -d 1 -b -p $pid ");
#if \*ERROR is false, STDERR is sent to STDOUT 

my $sel = new IO::Select();

$sel->add(\*READ);
$sel->add(\*ERROR);

while(1){

foreach my $h ($sel->can_read){
    my $buf = '';
        if ($h eq \*ERROR){
              sysread(ERROR,$buf,4096);
              if($buf){print "ERROR-> $buf\n"}
}else{

 sysread(READ,$buf,4096);
    if($buf){print "$buf\n"}
   }
  }
}

[download]
I'm not really a human, but I play one on earth. flash japh

Replies are listed 'Best First'.
Re^2: top and STDERR hell...
by DouglasDD (Beadle) on Jun 08, 2005 at 14:36 UTC
    Nope, still 80 cols (even after adding $ENV{'COLUMNS'} = 1000;).

    Neat tho', Both IPC::Open3, and IO::Select are new to me.

    ./ddd

[reply]
[d/l]
      If you are looking to fool the process into different columns, maybe you need to use IO::Pty. I havn't been able to figure it out myself, but there is something in "clone_winsize_from(\*FH)".

      I have this example in my collection, and I can't remember where I got it...probably google.groups or here. Anyway, it may have a few hints for you. 

      #!/usr/bin/perl -w
# Description: Fool a process into 
# thinking that STDOUT is a terminal, when in fact 
# it may be a file or a pipe. This can be useful 
# with programs like ps and w on linux... which 
# will trunc their output to the width of the 
# terminal, and, if they cannot detect the terminal 
# width, use a default 80 columns. Wouldn't it be 
# nice to say "ps -aux | grep etcshadow", and get 
# output that looks like when you just say "ps 
# -aux"? Well, that's the idea. 

#try ./pseudotty "xterm -e top" 
#or  ./pseudotty top 

use warnings;
use strict;
use IO::Pty;

die "usage: ptyexec command [args]\n" unless @ARGV;

my $pty = IO::Pty->new;
my $slave = $pty->slave;
open TTY,"/dev/tty" or die "not connected to a terminal\n";
$pty->clone_winsize_from(\*TTY);
close TTY;

my $pid = fork(); die "bad fork: $!\n" unless defined $pid;
if (!$pid) {
#  $slave->close(); 
  open STDOUT,">&=".$pty->fileno() or die $!;
  exec @ARGV;
}else{
  $pty->close();
     while (defined (my $line = <$slave>)) {
       print $line;
     }
}

#cleanup pty for next run 
$pty->close();

      [download]
      I'm not really a human, but I play one on earth. flash japh
[reply]
[d/l]
        <keanu-reeves-voice>Whoah!</keanu-reeves-voice>

        I'll play around with that code, but I don't think that I'll try to deliver a solution that's based on it. I know for a fact that code is an order of magnitude beyond the unix hackery knowledge of anyone else at this company. And being honest, I'll admit that a tad beyond mine as well.
        A good brain stretching excercise, but I don't want want my bread and butter to depend on it!

        ./ddd

[reply]
[d/l]
[select]

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