unable to write output of a fifo file to a log file

mithun119 · 10-09-2014, 09:48 AM

I am trying to read from a fifo file and append that along with the date to a log file.

I am able to write only the first line to the log "Starting the log".
But the write within the while loop after reading from the fifo doesnt happen.

It does only if I open the log file for writing within the while loop.
I want to be able to open the log for appending and write to it anywhere from the proceeding loops. Can someone please help fix the code.

#!/usr/bin/perl
use Path::Class;
#use autodie;

my $fifo = "pcode.pipe";
my $fifoh;
my $fifolog = "/nfs/home/kummit01/lab/fifo.log";

open($fifoh, "+< $fifo") or die "The FIFO file cant be found";

open (LOGH, "+>>$fifolog") or die "The Log file cant be opened";

print LOGH "Startintg the log\n";
while (<$fifoh>) {
chomp ($_);
$pattern = '^[A-Z]{1,2}[0-9]{1,2}?\s[0-9][A-Z][A-Z]$';
if ($_ =~ /$pattern/) {
#open (LOGH, ">>$fifolog") or die "The Log file cant be opened";
print "Match Success \n";
$timeNow = localtime(time);
print LOGH ("$_ $timeNow");
} else {
print "No Match \n";
}
}
close $fifoh;
close $logh;
exit (0);

linosaurusroot · 10-09-2014, 10:14 AM

To ensure output is not buffered

Code:

$|=1;

mithun119 · 10-09-2014, 10:36 AM

Quote:

Originally Posted by linosaurusroot

To ensure output is not buffered

Code:

$|=1;

Sorry but I am not clear with this.
Can you please show me where in the code to place this and how it works.

Thanks much.

linosaurusroot · 10-09-2014, 01:21 PM

After any print/printf that you want written immediately.

mithun119 · 10-09-2014, 03:06 PM

Quote:

Originally Posted by linosaurusroot

After any print/printf that you want written immediately.

I am still not able to do it.

Can you please modify part of the code and show how and where exactly to use it.

linosaurusroot · 10-10-2014, 06:55 AM

Code:

#!/usr/bin/perl -w

my $fifo = "pcode.pipe";
my $fifolog = "/nfs/home/kummit01/lab/fifo.log";
   $fifolog = "fifo.log";

open(F, "<$fifo") or die "The FIFO file cant be found";

open (LOGH, ">$fifolog") or die "The Log file cant be opened $!";
printf(LOGH "Starting the log\n");
$|=1;

while (<F>) {
 chomp($_);
 if (/^[A-Z]{1,2}[0-9]{1,2}?\s+[0-9][A-Z][A-Z]$/) {
   print "Match Success\n";
   $timeNow = localtime(time);
   printf(LOGH "%s - %s\n", $_, $timeNow);  $|=1;
 } else {
   print "No Match\n";
 }
}
exit (0);

If you've got stuck remove the pipe and make a new one.