Hi,
I'm writing a simple script which gets input from a fifo (which is fed by
syslog as well) and prints out the names and accounts uf "User unknow in
recipient table".
Here is the code:
===================
#!/usr/bin/perl
use strict;
use warnings;
# DUMP user table
open (USERS, "config/passwd") or die ("Unable to open PASSWD: $!\n");
my %users;
while(<USERS>) {
my($username,$uid,$gid) = (split(/:/,$_))[0,2,3];
#print "$gid\n";
next unless ($gid eq 100);
$users{$username}="";
}
close USERS;
# PARSE maillog from FIFO
open (FIFO, "</tmp/fifo-mennox") or die ("Unable to open FIFO for reading! $!");
open (OUTPUT, ">>unknown_users_list.txt") or die ("Unable to open OUTPUT for
writing! $!");
while(<FIFO>) {
next unless ($_ =~ /User unknown/);
my ($address) = $_ =~ /^.*to=<([^> ]+)>/;
my ($username) = (split(/\x40/,$address))[0];
next if $username =~ /^$/;
#printf OUTPUT ("%-50s\t%-20s\n",$address,$username) if
(exists($users{$username}));
printf OUTPUT ("%-50s\t%-20s\n",$address,$username);
}
close OUTPUT;
========================
The problem is that if I "tail -f" the output file for screening the results
while they are written, my script ends up writing at all.
No problem if I never open the file until I stop the execution of my script.
It seems I have a problem with a concurrent access to the same file, one in
"append" mode (my script), the other in read-only mode (tail -f).
Maybe tail (or 'cat' as well, it's the same) affects the file inode so that it
stops perl from writing?
Any help would be appreciated
TIA
Mariano
--
-----------------------------
Mariano Cunietti
System Administrator
Enter S.r.l.
Via Stefanardo da Vimercate, 28
20128 - Milano - Italy
Tel. +39 02 25514319
Fax +39 02 25514303
[EMAIL PROTECTED]
www.enter.it - www.enterpoint.it
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