The debug_echo function may be used to selectively send debugging messages to stderr and / or the system event log.
$1 - The message to be output.
$DEBUG - If this global variable is set then output will be sent to stderr.
$LOGGING - If this global variable is set then output will be sent to the system event log.
debug: This is a test messagemax@lisa ~ $ LOGGING="true" ./debug_echo.sh
Nov 14 17:54:11 lisa max: debug: This is a test messagemax@lisa ~ $ DEBUG="true" LOGGING="true" ./debug_echo.sh
debug: This is a test messagemax@lisa ~ $ tail /var/log/messages
Nov 14 17:54:33 lisa max: debug: This is a test message