There is an extensive log maintenance "kit" here: http://www.kixtart.org/ubbthreads/showflat.php?Cat=&Number=75703&page=&view=&sb=5&o=&vc=1

However, I think that this is a bit more fully featured than you need.

Here is a simple example of how you could do the size limit thing in KiXtart:
Code:
Function udfRotateLog($sPath,$iSize,Optional $iGenerations,Optional $bInitLog)



	Dim $sMask,$i,$fd



	If Not CInt($iGenerations) $iGenerations=1 EndIf

	If Not CInt($bInitLog) $bInitLog=0 EndIf

	$iSize=CDBL($iSize)



	While Len($sMask)<Len($iGenerations) $sMask=CSTR($sMask)+"0" Loop



	If GetFileSize($sPath)>=$iSize

		; Sanity check - Ignore

		;	1	Read Only

		;	4	System

		;	16	Direcroty

		;	256	Temporary

		;	4096	Offline

		If (1+4+16+256+4096) & GetFileAttr($sPath) Exit 1 EndIf

		If @ERROR Exit @ERROR EndIf

		; Remove oldest generation

		Del $sPath+"."+$iGenerations

		; Rotate existing log files

		For $i=$iGenerations To 2 Step -1

			Move $sPath+"."+Right($sMask+($i-1),Len($iGenerations)) $sPath+"."+Right($sMask+$i,Len($iGenerations))

			; Ignore "file not found"

			If Not(@ERROR=0 OR @ERROR=2) Exit @ERROR EndIf

		Next

		; Now move primary log file

		Move $sPath $sPath+"."+Right($sMask+1,Len($iGenerations))

		If @ERROR Exit @ERROR EndIf

		; Finally, create an empty log file if needed

		If $bInitLog

			$fd=FreeFileHandle()

			If @ERROR Exit @ERROR EndIf

			If Open($fd,$sPath,1+4) Exit @ERROR EndIf

			$=Close($fd)

		EndIf

	EndIf

	Exit 0

EndFunction


Parameters are:
  • $sPath - Path to your log file.
  • $iSize - When file reaches this size (in bytes) it is rotated. If you set this to zero, the file is always rotated.
  • $iGenerations - How many generations of the file to keep
  • $bInitLog - Set to true if you want to create an empty file once the log file has been rotated.


So to keep 50 MB of history, and create an empty file after the rotation:
Code:
$sLogFile="c:\foo\mylogfile.txt"

$iMaxSize=10*1024*1024 ; 10 Megabytes

$iMaxHistory=5

 

udfRotateLog($sLogFile,$sMaxSize,$iMaxHistory,1)