One task I often find myself doing is running a java program on each member of a dataset. If the java program is configured to run in the background, you will initiated enough java calls to crash your computer. I hacked together a solution using perl that waits for each call to java to finish before initiating the next.
#!/usr/bin/perl
use strict;
my (@fileA,@out);
#put java command into string
my $command = "./java.sh";
#simulate multipul calls with foreach loop
foreach my $wait (1..20){#represents the iterations of inputs run via a java program
#open a handle for the command, piping into $java
open my $java, '-|', $command or die "Could not run java ... - $!";
#while handle is still be written to, print .
print "running command ${wait}";
while (<$java>) {
print ".";
#push the output of the command into file array
@fileA = <$java>;
}
push(@out, @fileA);
#close the pipe when the command is done
close($java);
}
#print to some output file
my $file = "out.txt";
#open it, print to it the @out array, close it, print \n
open my $f, '>', $file;
print $f @out;
close $f;
print "\n";
#java.sh
#############################################
#!/bin/bash
#java -classpath /home/user/pathto/jarFile.jar ducks.main &
############################################
