passing a parameter to an outside program

asr055 has asked for the wisdom of the Perl Monks concerning the following question:

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Re: passing a parameter to an outside program by ikegami (Patriarch) on Oct 05, 2005 at 20:51 UTC
The child needs to print the data out to standard input (which the parent must have ready to capture) or to a temporary file (whose name the parent might have passed as an argument). The simple case where the parent waits for the child to complete can be written as: parent ------ $result = `child.pl`; child ----- print($result); [download]	[reply] [d/l]
Re: passing a parameter to an outside program by InfiniteSilence (Curate) on Oct 05, 2005 at 21:29 UTC
There are many ways to do this. Here are a few not yet mentioned: envpass.pl: `#!/usr/bin/perl -w use strict; #set environment variables $ENV{FOOBAR} = 10000; #Set package level variables package manic; our $vroom = 10097; #You can use Data::Dumper package main; use Data::Dumper; my $foobie = 19897; open(H,qq\|>junk.dat\|) or die $!; print H Data::Dumper->Dump([$foobie],[qw[foobie]]); close(H); 1;` [download] envpass2.pl #!/usr/bin/perl -w use strict; do 'envpass.pl'; print $ENV{FOOBAR}; print $manic::vroom; #read in that data dumper stuff my $stuff = `cat junk.dat`; no strict 'vars'; eval($stuff); print $foobie; 1; [download] Celebrate Intellectual Diversity	[reply] [d/l] [select]
Re: passing a parameter to an outside program by Skeeve (Parson) on Oct 05, 2005 at 20:58 UTC
If you need more complex parameter passing than what ikegami mentioned, you might like to look at perldoc perlipc `$\=~s;s.;q^\|D9JYJ^^qq^\//\\\///^;ex;print`	[reply] [d/l]
Re: passing a parameter to an outside program by Roy Johnson (Monsignor) on Oct 05, 2005 at 21:42 UTC
That depends on how you're calling the other program. If you're using backticks, the called program can just print the string and the calling program will capture it. Caution: Contents may have been coded under pressure.	[reply]
Re: passing a parameter to an outside program by nedals (Deacon) on Oct 05, 2005 at 22:04 UTC
You might also want to take a look at.. LWP::UserAgent	[reply]
Re: passing a parameter to an outside program by samizdat (Vicar) on Oct 06, 2005 at 15:02 UTC
I'm not clear from your question whether you want to only communicate at the end of the child process or while both are running concurrently. If the former is truly what you want, then the answers about backticks et al are appropriate. Environment variables are also fairly easy, but you can only use them when the programs are spawned from the same shell. IPC in a more general sense, through sockets or shared memory, is much more complicated but also much more powerful. And, a caveat, all of the more powerful suggestions imply that you are on a *NIX system of one kind or another, not a Windows box.	[reply]