Passing an array into an open command

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

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Re: Passing an array into an open command by tcf22 (Priest) on Mar 18, 2004 at 18:12 UTC
It looks like it should work. I tried the following on Win32 Active Perl 5.8. test1.pl `my @a; foreach(1..50){ $a[$_-1] = $_; } open(T, "test2.pl @a\|"); while(<T>){ print; } close(T);` [download] test2.pl `foreach(@ARGV){ print "$_\n"; }` [download] If I run test1.pl, I get 1..50 printed out on seperate lines, just like you would expect. UPDATE: Also works on Red Hat Linux 9. (Just change `"test2.pl @a\|"` to `"./test2.pl @a\|"` of course). - Tom	[reply] [d/l] [select]
Re: Re: Passing an array into an open command by amw1 (Friar) on Mar 18, 2004 at 18:16 UTC
with passing @a to the script would you run into limits of a commandline if @a is say 10,000 elements, or does the exec not care? (it's been a long time since I've played with this)	[reply]
Re: Re: Re: Passing an array into an open command by tcf22 (Priest) on Mar 18, 2004 at 18:36 UTC
Linux allows me to go up to around 23,000. Windows however crashed when i reach 530. I assume that there is some size or argument limit on most Oper. Systems. - Tom	[reply]
Re: Passing an array into an open command by eXile (Priest) on Mar 18, 2004 at 20:19 UTC
Mike, is the 'ticket' program expecting input from the command-line or on STDIN? If it is expecting input from STDIN and you want to process it's STDOUT, you can use IPC::Open2: test3.pl (emulates 'ticket' program') `#!/usr/bin/perl -w use strict; while (<STDIN>) { print "PROCESSED $_"; }` [download] test4.pl `#!/usr/bin/perl -w use strict; $\|++; use IPC::Open2; my @loglines=("This is not a relevant logline", "This is not a relevant logline", "This might be an interesting logine", "Another interesting logline"); open2(READ,WRITE,"./test3.pl") or die; foreach my $inputline (@loglines) { print WRITE "$inputline\n"; } close (WRITE); my $outputline; while ($outputline = <READ>) { print $outputline; }` [download] As a sidestep: if you use 'open', please check if it succeeds, like: `open(RUN, "/usr/local/bin/ticket @ABC\|") or die "useful error message +here";` [download]	[reply] [d/l] [select]
Re: Passing an array into an open command by NovMonk (Chaplain) on Mar 18, 2004 at 18:13 UTC
Shouldn't it be `while (<RUN>){ print $line; }` [download] ? If I'm completely missing the boat, I trust one of my brother/ sister monks will be gentle with their enlightenment.... Good luck, NovMonk	[reply] [d/l]
Re^2: Passing an array into an open command by Nkuvu (Priest) on Mar 18, 2004 at 19:03 UTC
I don't think so. the `while (<RUN>)` assigns the line from the RUN filehandle to `$_`, then you print out `$line` (which hasn't been assigned anything in this snippet). I don't think that's what the OP wants.	[reply] [d/l] [select]
Re: Re^2: Passing an array into an open command by NovMonk (Chaplain) on Mar 18, 2004 at 19:12 UTC
Ah. I see. I was trying to identify that what he wanted to do was run through his <RUN> and print something-- I just used his $line variable without thinking about what that does. Oh well. At least I knew his `while ($line= <RUN>`... was a problem. I may get the hang of this yet. Thanks for the feedback. pax, NovMonk	[reply] [d/l]
Re: Passing an array into an open command by Roy Johnson (Monsignor) on Mar 18, 2004 at 20:04 UTC
Any chance you've got newlines in your @ABC data? Have you printed out what the command line you assemble looks like? What does the output of 49 from the ticket program indicate? The PerlMonk `tr///` Advocate	[reply]
Re: Passing an array into an open command by amw1 (Friar) on Mar 18, 2004 at 18:10 UTC
Here's how I'd do it. `#populate @ABC for pourposes of the test @ABC = qw[ticket1 ticket2 ticket3]; foreach my $ticket (@ABC) { my $line = qx{/usr/local/bin/ticket $ticket}; # print qx{.... would also accomplish this # assuming you want to do more to $line than print print $line; }` [download] nevermind, missed the fact that all args were needed at once. sigh	[reply] [d/l]
Re: Passing an array into an open command by ambrus (Abbot) on Mar 18, 2004 at 20:00 UTC
You might try using the new "three-argument" form of the open func, but it will have more than three arguments here.	[reply]


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