Contents: debug.txt - contains debugging information; opened in overwrite mode ('>') per request debug.log - contains debugging information; opened in append mode ('>>'); rotated using log_rotate.pl (count => 3) sql.txt - contains SELECT query statements from application in production mode; opened in append mode; rotated using log_rotate.pl (count => 3) dev_sql.txt - contains SELECT query statements from application in development mode; rotated using log_rotate.pl (count => 3) {yyyy_mmdd}_sql.log - contains UPDATE/INSERT/DELETE statements from application in production mode; archived in /old daily using log_rotate.pl dev_sql.log - contains UPDATE/INSERT/DELETE statements from application in development mode; rotated using log_rotate.pl (count => 3) file ownership: sql.txt 666 raj:raj debug.log 666 raj:raj dev_sql.log 644 raj:raj dev_sql.txt 644 raj:raj yyyy_mmdd_sql.log 666 www-data:www-data To truncate file in use: sudo cp new_msgs.log new_msgs.log.nn && sudo cat /dev/null > new_msgs.log sudo chown raj:raj new_msgs.log.nn