Re^2: Run Perl script in perl program with new process group

in the output we are getting PGRP different from PID 31852 1 31851 18307 /usr/bin/perl ./perl.pl 31854 31852 31851 18307 \_ sleep 1 31852 is different from 31851... i am trying to start the perl.pl in background with PID = PGRP.. if i start the job without Background.. it works as expected but when i start the job on Background(&).

Comment on Re^2: Run Perl script in perl program with new process group

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Re^3: Run Perl script in perl program with new process group by gmargo (Hermit) on Dec 18, 2009 at 13:55 UTC
If you start a job in the foreground (`my $cmd = qq{nohup ./perl.pl};`), then the process id (PID) and process group (PGRP) will match, because perl will exec the program directly. If you start a job in the background (`my $cmd = qq{nohup ./perl.pl &};`), then the process id (PID) and process group (PGRP) will NOT match, because perl notices the shell meta-character '&' and execs a shell directly, and the shell will exec the program. The PGRP you are seeing is the PID of the shell that was started solely to process the backgrounding character. Since you're already `fork`ing, why do you need the implied fork of the '&' character too?	[reply] [d/l] [select]
Re^4: Run Perl script in perl program with new process group by veshwar (Initiate) on Dec 18, 2009 at 16:09 UTC
i need to make the process (my $cmd = qq{nohup ./perl.pl};) a daemon process. if i remove the &, it remains connected with the shell and i cannot disconnect the script. I have tried to start my script in background and starting process without &. It works but the ppid(20753) is still connected to shell which is closing on the logout. $ ps -ef -o "user,pid,ppid,pgid,args" \| grep perl.pl userid 22542 20753 22542 /usr/bin/perl ./perl.pl Is there anyway i can change the ppid of this process to 1 without loggingout for the session.	[reply]