Набросал тут на Perl немного:

#!/usr/bin/perl
use strict;

use Getopt::Long;
my $source_file = "";
my $set_of_world = "";
my $result_file;
my @set_of_world = ();

GetOptions("source=s" => \$source_file,
"set=s" => \$set_of_world,
"result=s" =>\$result_file);

unless ($source_file && $set_of_world ) {
Usage();
}

open(fd_set, "$set_of_world");
while(<fd_set>) {
chomp $_;
push @set_of_world, $_;
}
close(fd_set);

open(fd_source, "$source_file") or die "Can't open $source_file: $!\n";
if(defined($result_file)) {
open(fd_result, ">$result_file");
}
while(<fd_source>) {
chomp $_;
my($a, $b, $c, $d) = split(' ', $_);
if(defined($result_file)) {
print fd_result "$a $b ".$set_of_world[rand @set_of_world]." $d\n";
}
else {
print "$a $b ".$set_of_world[rand @set_of_world]." $d\n";
}
}
if(defined($result_file)) {
close(fd_result);
}
close(fd_source);

sub Usage() {
print "Usage: perl ./script.pl --source=source.txt --set=set.txt [--result=result.txt]";
exit 0;
}