On Thu, Mar 27, 2014 at 3:00 PM, Philip Guenther <guent...@gmail.com> wrote:
> On Thu, Mar 27, 2014 at 2:28 PM, sven falempin <sven.falem...@gmail.com>
> wrote:
>> Sometimes i feel curse (or maybe just tired) :
>>
>> main::(/bin/check_network.pl:164): my $src =
>> system('/usr/bin/pkill -HUP -f "dhclient: trunk0"');
>> DB<2> n
>> main::(/bin/check_network.pl:165): if ($src) {
>> DB<2> p $src
>> 33024
>>
>> Of course pkill is supposed to return 0,1,2 or 3 and it does in the shell
>
> perldoc -f system
> ...
> The return value is the exit status of the program as returned
> by the "wait" call. To get the actual exit value, shift right
> by eight (see below). See also "exec". This is not what you
>
> 33024 >> 8 == 129
(Stupid gmail control-enter==Send)
So, why is it returning 129? Well, since you gave system() a single
string it's actually invoked via the shell. Why would the shell
report a status of 129?
? The exit status of the last non-asynchronous command executed.
If the last command was killed by a signal, $? is set to 128
plus the signal number.
So, pkill is dying with signal 1 == HUP. Hey, wait a minute, pkill's
criteria matches its own command line, so it will kill itself! Time
to be more clever about the criteria...
Philip Guenther
