Question

perl - execute a system shell command & do not wait for completion

Asked by: lbdev

In perl, how can I execute a system shell command, but not wait for the command to complete?

I am used to using the backtick method as shown below, but I do not want to wait several seconds for the command to complete before the perl script continues.

I do not need a return value.

#!/usr/bin/perl
 
`bashcommand < whatever.txt`;
 
perlstuff();
exit;

                                  
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Asked On
2009-09-22 at 00:58:18ID24750753
Tags

perl

Topic

Perl Programming Language

Participating Experts
2
Points
500
Comments
5

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Answers

 

by: mnialonPosted on 2009-09-22 at 01:08:40ID: 25390493

hello
did you with ampersand (&) at the end of your command to run it in background mode?

 

by: mnialonPosted on 2009-09-22 at 01:09:44ID: 25390497

like that :
`bashcommand < whatever.txt&`;


 

by: lbdevPosted on 2009-09-22 at 01:19:55ID: 31631781

Oh man, I feel stupid now. =)

Thanks for the help!

 

by: lbdevPosted on 2009-09-22 at 01:29:58ID: 25390611

actually, the ampersand works... but not with backticks, only with exec().


#!/usr/bin/perl
 
use strict;
use warnings;
 
print "starting\n";
 
#PERL SCRIPT WAITS 5 SECONDS
`sleep 5 &`; 
 
#PERL SCRIPT EXECUTES AND CONTINUES WITHOUT WAITING
exec ('sleep 5 &');
 
print "ending\n";

                                              
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by: TintinPosted on 2009-09-22 at 03:20:04ID: 25391135

exec isn't what you need as it effectively exits the script at that point.

What you are really after is fork.

20120131-EE-VQP-002

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