Restarting perl script by itself

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

Replies are listed 'Best First'.
Re: Restarting perl script by itself by ChuckularOne (Prior) on Sep 16, 2011 at 17:48 UTC
I have recently done something similar, but I decided to let cron do the killing. My process starts by creating a kill script and then cron executes it once a day and then spawns a new instance of the main script which creates a new kill script and it gets a little like groundhog day. `### Create the kill script for cron ### my $killPid = $$; bifFile::writeToFile($killscript, "kill $killPid"); my $mode = '0755'; chmod oct($mode), $killscript;` [download] $killscript is the path and name of the script (a ksh script in this case) and bifFile is a perl module full of silly little utilities I use all the time. writeToFile uses two parameters, filename and text to put in the file.	[reply] [d/l]
Re: Restarting perl script by itself by kennethk (Abbot) on Sep 16, 2011 at 17:06 UTC
Something closer to what you are looking for can be found in Complete Dissociation of Child from Parent in perlipc. As the doc mentions, you might also look for a Your_OS::Process module on CPAN.	[reply]
Re: Restarting perl script by itself by Anonymous Monk on Sep 16, 2011 at 15:54 UTC
You're not forking a new process, running something in there, and then killing your current process. You're just doing a full-brain transplant on yourself.	[reply]
Re^2: Restarting perl script by itself by manua (Novice) on Sep 16, 2011 at 17:19 UTC
Thanks. As per my understanding, exec will launch the new process, which should have a different process id than the parent process and parent process will not wait for the child process to complete. And, when the script complete, the parent process will be automatically killed. Let me know, what I am doing wrong.	[reply]
Re^3: Restarting perl script by itself by zentara (Cardinal) on Sep 16, 2011 at 17:24 UTC
As per my understanding, exec will launch the new process No, exec *replaces* your current process.... a subtle difference. I'm not really a human, but I play one on earth. Old Perl Programmer Haiku ................... flash japh	[reply]
Re^4: Restarting perl script by itself by manua (Novice) on Sep 16, 2011 at 19:31 UTC
Re^3: Restarting perl script by itself by afoken (Chancellor) on Sep 16, 2011 at 17:28 UTC
exec replaces one process with another one, keeping the PID, file descriptors, environment and so on. No single command launches a child process, keeping the parent process paralysed, and finally kills the helpless parent. Simply because that would be very inefficient. You should really RTFM, especially fork, exec, and system. Also read wait and waitpid. Understanding the concept of fork and exec is essential for writing software on Unix-like systems. Alexander -- Today I will gladly share my knowledge and experience, for there are no sweeter words than "I told you so". ;-)	[reply]