best way to kill a spawned process

redss has asked for the wisdom of the Perl Monks concerning the following question:

What is the best way to kill a system command spawned from my program? For example:

system "arecord file.wav";
# at some point in program user wants to end recording
system "killall arecord";
[download]

Is there a better preferred way to do that in perl?

Comment on best way to kill a spawned process Download Code

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Re: best way to kill a spawned process by tobyink (Canon) on Feb 05, 2013 at 16:47 UTC
`use strict; use warnings; if (my $child = fork) { # foreground process sleep 5; kill 9, $child; } else { # background process exec("arecord", "file.wav"); }` [download] The `fork` plus `exec` combination allows you to cleanly launch a background process, and gives you the PID for the background process, which can later be passed to `kill`. `package Cow { use Moo; has name => (is => 'lazy', default => sub { 'Mooington' }) } say Cow->new->name`	[reply] [d/l] [select]
Re^2: best way to kill a spawned process by redss (Monk) on Feb 05, 2013 at 17:19 UTC
That works...thanks!	[reply]
Re^3: best way to kill a spawned process by Anonymous Monk on Feb 05, 2013 at 17:44 UTC
Take his choice of signal with a large grain of salt [1]: No no no. Don't use kill -9. It doesn't give the process a chance to cleanly: 1) shut down socket connections 2) clean up temp files 3) inform its children that it is going away 4) reset its terminal characteristics and so on and so on and so on. Generally, send 15, and wait a second or two, and if that doesn't work, send 2, and if that doesn't work, send 1. If that doesn't, REMOVE THE BINARY because the program is badly behaved! Don't use kill -9. Don't bring out the combine harvester just to tidy up the flower pot. Just another Useless Use of Usenet, [1] http://www.partmaps.org/era/unix/award.html#uuk9letter	[reply]