Sorry Jochen,
My real script has the $CRLF defined.

I have tested both of your scripts and both of them seem to go into an endless loop with a file size of Zero bytes.

Code Sample 1

code:

---

$crlf = chr(13)+chr(10) ;chr(13) is a Carriage Return and chr(10) is a line feed
$CHK = "Unknown"
BREAK ON
$logfile = "C:\RC.TXT"
$ = OPEN(1,$logfile,2)
	IF @error = 0
		$x = readline(1)
			IF $x OR asc($x) = $crlf
				DO
					SELECT
						CASE instr($x,"rtvscan.exe")
							$CHK = "Running"
					ENDSELECT
					$x = readline(1)
				UNTIL @error
			ENDIF
	ENDIF
$ = CLOSE(1)

---

Code Sample 2

code:

---

BREAK ON
$CHK = ""
$logfile = "C:\RC.TXT"
$ = OPEN(1,$logfile,2)
IF @error = 0
 $x = readline(1)
 while @error = 0
  if instr($x,"rtvscan.exe")
    $CHK = "Running"
  endif
  $x = readline(1)
 LOOP
 $ = CLOSE(1)
ENDIF
?"CHK=$CHK"
EXIT 1

---

As I said before, if there is "anything" in the file the code works fine. If it has a size of at lest 2 bytes "a $cr" it works. If it has nothing it loops forever till you break out of it manually.

I'm using KiXtart v3.63 on Windows 2000 Pro SP2

NOTE:
I just now tested this on KiXtart 2001 RC3 and it works fine. It DOES NOT work on KiXtart v3.63 Is this a bug or some other known issue?