#...
  open(PLAINTEXT,">Plain") || print "Error to write to the file";
  print PLAINTEXT "$server\|$login\|$password\n";·
  local $/;
  $plaintext = <PLAINTEXT>;
  close(PLAINTEXT);
#...

##</code><code>##

#...
$plaintext = "$server\|$login\|$password\n";
#...