perl - tee

tee.pl

#! /usr/bin/perl

# usage: ping 8.8.8.8 | tea.pl [-v] [-t] [FILE]
# -v = verbose | -t = prefix timestamp to output | FILE = output filename

use IO::Handle;
use Getopt::Long;
use Time::HiRes;
use POSIX;

sub cmd_args
{
 GetOptions("time|t", \$time, "verbose|v", \$verbose) or die $!;
}

sub now
{ 
 my ($secs, $us) = Time::HiRes::gettimeofday;
 my $dt = strftime(q/%Y-%m-%d %H:%M:%S./, localtime($secs)) . sprintf("%06d", $us);
 return $dt;
}

sub main
{
 $f = $ARGV[0] || "tea." . $^T . ".log"; # create an epoch padded filename if ARGV is null

 open OUT, '>', $f || die "$!\n";
 OUT->autoflush(1);
 
 while (<STDIN>) 
 {
  if ($time)
  {
   if (! /\S/)
   { 
    print $_; # <-t> enabled but do not prefix <blank> lines
    print OUT $_; # <-t> enabled but do not prefix <blank> lines
   }
   else
   {
    print now() . ": " . $_; # to STDOUT with timestamp prefix
    print OUT now() . ": " . $_; # to FILE with timestamp prefix
   }
  }
  else # [-t] not enabled - output to STDOUT & FILE verbatum
  {
   print $_;
   print OUT $_;
  }   
 }
 close OUT;
}

cmd_args;

main;

exit;