A completely different approach would be to use my execute code which I reposted here. Basically, it will run a command line application without a shell, so there's less overhead. It also captures the output, so it is 'loading to a variable' which might fit your request better. HTH, SSF.

sub execute {       # execute a command without shell but with timeout
   my ($cmd,@args)=@_;
   my $timeout=15;  # seconds
   my ($result,$pid,$i);
   if ($args[$#args]=~/^--?timeout=(\d+)$/i) {  # or pass as last arg
      $timeout=$1;
      pop @args;
   }
   $i=index($cmd,' ');   # args appended to command?
   if ($i>-1) {
      unshift @args,split(/\s+/,substr($cmd,$i+1));   # could be more 
+than one
      $cmd=substr($cmd,0,$i);
   }
   eval {
        local $SIG{ALRM} = sub { die "alarm\n" }; # NB: \n required
        local($/)=undef;
        alarm $timeout;
        $pid=open(CMD,'-|',$cmd,@args);   # run without shell overhead
        if ($pid) {
           $result=<CMD>;
           close CMD;
        } else {
           alarm 0;
        }     
        alarm 0;
    };
    if ($@) {
        die $@ unless $@ eq "alarm\n";   # propagate unexpected errors
    }
    $result;
}
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