Harry Putnam wrote:
>
> What is the handy way to record the pid of $some_process in this
> fake code?
>
> $some_process = 'tcpdump -v -ieth0 >file')
> system("$some_process") or die "Can't start $some_process: $!";
system() returns false on success and true on failure so "or die ..."
will execute when system() succeeds and the $! variable does not contain
any useful information, you need $? instead.
perldoc -f system
> print "Pid is $pid\n";
>
> The process is started by a more elaborate perl script at bootup.
> and restarted every four hours from syslog. Code above is way simplified.
open FILE, '>file' or die "Cannot open file: $!";
my $pid = open DUMP, 'tcpdump -v -ieth0 |' or die "Cannot open pipe from
tcpdump: $!";
print FILE while <DUMP>;
close DUMP or die "Cannot close pipe from tcpdump: $!";
close FILE;
print "Pid was $pid\n";
__END__
John
--
use Perl;
program
fulfillment
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