synwave7,
I tossed together the basics of reading and writing. If, however you want to remove those lines from log.txt and keep log.txt, that is another matter.
code:

Break on
$CRLF=CHR(13)+CHR(10)
If Exist("c:\kix4.02\newlog.txt")
  Del "c:\kix4.02\newlog.txt"
EndIf
If Open(1,"c:\kix4.02\newlog.txt",5) <> 0
  ? "Newlog file not opened, error code: [" + @ERROR + "]"
  GoTo skip
EndIf
If Open(2,"c:\kix4.02\log.txt") = 0
  $line = ReadLine(2)
  WHILE @ERROR = 0
    ? "Line read: [" + $line + "]"
    If instr($line, "20020126") <> 0
      WriteLine(1,$Line+$CRLF)
    Endif
    $line = ReadLine(2)
  LOOP
  Close (2)
ELSE
  BEEP
  ? "Log file not opened, error code: [" + @ERROR + "]"
EndIf

:skip
Close (1)
get $_
_________________________
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