Re: Interactive programs & Teeing

In article <1164665393.691544.228200@xxxxxxxxxxxxxxxxxxxxxxxxxxxx>,
conrado.blasco@xxxxxxxxx wrote:

I'm trying to write an interactive script that gets commands from
STDIN, prints the results to STDOUT, *and* tees the results to a log
file.

My problem is that when I add the teeing line to the program (see
below), the script doesn't print anything to STDOUT anymore (not even
the prompt). When I comment out that line, everything works fine
(except that I don't get the log file).

(Well, it actually still prints something, but only when the session is
over.)

It seems to me that I'm missing something very obvious, but I can't
figure out... Any help appreciated.

Relevant excerpt below:

#!/usr/bin/env perl
use warnings; # Needed since '-w' won't work on the shebang line
use strict;
use File::Basename;

my $my_name = fileparse($0);

# STDOUT prints on the screen as well as on to log file
open (STDOUT, "| tee ./" . $my_name . ".log")
or die "Teeing error: $!\n";

my $prompt = "$my_name > ";

# Main loop, read and parse standard input
print $prompt;
while (<STDIN>) {
parse_cmdline($_);
print $prompt;
}

It sounds like a buffering problem. Try adding $|++; near the top.

Boyd
.

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