#include <MsgBoxConstants.au3> ; to declare the Constants of MsgBox
Local $sRegex = "(?m)^(.*)JSESSIONID=.*((?=\"\s\").*)$"
Local $sString = "189.222.1.46 - - [24/Jul/2014:11:27:00] "GET /flower_store/product.screen?product_id=RP-SN-01 HTTP/1.1" 200 10897 "http://mystore.splunk.com/flower_store/category.screen?category_id=BALLOONS&JSESSIONID=SD1SL10FF3ADFF3" "Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.8.0.10) Gecko/20070223 CentOS/1.5.0.10-0.1.el4.centos Firefox/1.5.0.10" 527 3006" & @CRLF & _
"10.2.91.38 - - [24/Jul/2014:11:28:00] "POST /flower_store/j_signon_check HTTP/1.1" 302 309" & @CRLF & _
""http://mystore.splunk.com/flower_store/enter_order_information.screen&JSESSIONID=SD1SL10FF3ADFF3" "Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.8.0.10) Gecko/20070223 CentOS/1.5.0.10-0.1.el4.centos Firefox/1.5.0.10" 3441 2576" & @CRLF & _
"192.0.1.38 - - [24/Jul/2014:11:28:15] "GET /flower_store/images/cat3.gif HTTP/1.1" 200 5024 "http://mystore.splunk.com/flower_store/item.screen?item_id=EST-21&JSESSIONID=SD1SL10FF3ADFF3" "Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.8.0.10) Gecko/20070223 CentOS/1.5.0.10-0.1.el4.centos Firefox/1.5.0.10" 4323 3071"
Local $sSubst = "$1JSESSIONID=#######$2"
Local $sResult = StringRegExpReplace($sString, $sRegex, $sSubst)
MsgBox($MB_SYSTEMMODAL, "Result", $sResult)
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for AutoIt, please visit: https://www.autoitscript.com/autoit3/docs/functions/StringRegExp.htm