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See also 
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Developer's Bible, 
Technical Overview
  internal package Foswiki::Logger::PlainFile::Obfuscating  is a Foswiki::Logger::PlainFile 
Plain file implementation of the Foswiki Logger interface, with obfuscation
of IP addresses.  See 
Foswiki::Logger::PlainFile for further details.
This implementation only implements log() call.
This logger implementation maps groups of levels to a single logfile, viz. 
-  debugmessages are output to $Foswiki::cfg{Log}{Dir}/debug.log
-  infomessages are output to $Foswiki::cfg{Log}{Dir}/events.log
-  warning,error,critical,alert,emergencymessages are     output to $Foswiki::cfg{Log}{Dir}/error.log.
-  error,critical,alert, andemergencymessages are also     written to standard error (the webserver log file, usually)
 ObjectMethod log($level, @fields) 
See 
Foswiki::Logger for the interface.