use::warnings;
use::strict;

my $rmthost  = 'backupserver';
my $rmtuser  = 'anonymous';
my $rmtpath  = 'tempdir';
my $lclpath  = '/home/user/testdir';
my $lclglob  = '*.txt';
my $flagfile = '.last_backup';
my $r_opts   = "'ssh -l $rmthost $rmtuser'";
my $lclfiles = "$lclpath/$lclglob";

sub modtime {
  my $file  = shift;
  my @stats = stat $file or return 0;
  return $stats[9];
}

while (1) {
  my $timestamp = modtime("$lclpath/$flagfile");
  my $run = grep {modtime($_) > $timestamp} glob $lclfiles;
  if ($run) {
    system "scp  $r_opts $lclfiles $rmthost:$rmtpath";
    open  FLAG, ">$lclpath/$flagfile" or die;
    close FLAG or die;
  }
  sleep 60;
}