cat /tmp/test.log
===========================================================================
system Version [45.2.18] (FATAL ERROR INFORMATION)
File: [test003.cxx]
Line: [240]

Date: [19-01-2018 21:09:40]
User ID: [SYSTEM]
Message : [batman error: Upload_Msg_testListeningFn]
Error Code : [TEST0000057]
Outside FGH
Session Id: 6768678898:00:F

=======================================

Date: [19-01-2018 21:09:40]
Message : [batman error: Upload_Msg_testListeningFn]

awk '/^Date/{c=3} c&&c--' /tmp/test.log