use warnings;
use strict;
use Net::SFTP::Foreign;

my $host = 'xxx.xxx.xxx.xxx';
my $user = 'user';
my $pass = 'pass';
my $file = 'whatever';
my $contents;

my $sftp = Net::SFTP::Foreign->new
          ($host,
            backend => 'Net_SSH2',
            username => $user,
            password => $pass);

$sftp->error and
  die "Unable to establish SFTP connection: "
      . $sftp->error;

close STDOUT;
open STDOUT, '>', \$contents or die "Can't open STDOUT: $!";

$sftp->get($file, \*STDOUT) or die "get failed: " . $sftp->error;

warn $contents;