cronolog(1m)															      cronolog(1m)

NAME

       cronolog - write log messages to log files named according to a template

SYNOPSIS

       cronolog [OPTION]... template

DESCRIPTION

       cronolog  is  a simple program that reads log messages from its input and writes them to a set of output files, the names of which are con-
       structed using template and the current date and time.  The template uses the same format specifiers as the Unix date(1) command (which are
       the same as the standard C strftime library function).

       Before writing a message cronolog checks the time to see whether the current log file is still valid and if not it closes the current file,
       expands the template using the current date and time to generate a new file name, opens the new file (creating missing directories  on  the
       path of the new log file as needed unless the program is compiled with -DDONT_CREATE_SUBDIRS) and calculates the time at which the new file
       will become invalid.

       cronolog is intended to be used in conjunction with a Web server, such as Apache to split the access log into daily or monthly  logs.   For
       example the Apache configuration directives:

	       TransferLog "|/usr/bin/cronolog /www/logs/%Y/%m/%d/access.log"
	       ErrorLog    "|/usr/bin/cronolog /www/logs/%Y/%m/%d/errors.log"

       would instruct Apache to pipe its access and error log messages into separate copies of cronolog, which would create new log files each day
       in a directory hierarchy structured by date, i.e. on 31 December 1996 messages would be written to

	       /www/logs/1996/12/31/access.log
	       /www/logs/1996/12/31/errors.log

       after midnight the files

	       /www/logs/1997/01/01/access.log
	       /www/logs/1997/01/01/errors.log

       would be used, with the directories 1997, 1997/01 and 1997/01/01 being created if they did not already exist.  (Note that prior to  version
       1.2 Apache did not allow a program to be specified as the argument of the ErrorLog directive.)

Options
       cronolog accepts the following options and arguments:

       -H NAME

       --hardlink=NAME
	      maintain a hard link from NAME to the current log file.

       -S NAME

       --symlink=NAME

       -l NAME

       --link=NAME
	      maintain a symbolic link from NAME to the current log file.

       -P NAME

       --prev-simlink=NAME
	      maintain	a  symbolic link from NAME to the previous log file.  Requires that the --symlink option is specified, as cronolog renames
	      the current link to the name specified for the previous link.

       -h

       --help print a help message and then exit.

       -p PERIOD

       --period=PERIOD
	      specifies the period explicitly as an optional digit string followed by one of  units:  seconds,	minutes,  hours,  days,  weeks	or
	      months.	The  count  cannot be greater than the number of units in the next larger unit, i.e. you cannot specify "120 minutes", and
	      for seconds, minutes and hours the count must be a factor of the next higher unit, i.e you can specify 1, 2, 3, 4, 5, 6, 10, 15,	20
	      or 30 minutes but not say 7 minutes.

       -d PERIOD

       --delay=PERIOD
	      specifies  the delay from the start of the period before the log file is rolled over.  For example specifying (explicitly or implic-
	      itly) a period of 15 minutes and a delay of 5 minutes results in the log files being rotated at five past, twenty  past,	twentyfive
	      to and ten to each hour.	 The delay cannot be longer than the period.

       -o

       --once-only
	      create single output log from template, which is not rotated.

       -x FILE

       --debug=FILE
	      write debug messages to FILE or to the standard error stream if FILE is "-".  (See the README file for more details.)

       -s TIME

       --start-time=TIME
	      pretend  that the starting time is TIME (for debugging purposes).  TIME should be something like DD MONTH YYYY HH:MM:SS (the day and
	      month are reversed if the american option is specified).	If the seconds are omitted then they are taken as zero and  if	the  hours
	      and minutes are omitted then the time of day is taken as 00:00:00 (i.e. midnight).  The day, month and year can be separated by spa-
	      ces, hyphens (-) or solidi (/).

       -a

       --american
	      Interprete the date part of the starting time the American way (month then day).

       -e

       --european
	      Interprete the date part of the starting time the European way (day then month).	This is the default.

       -v

       --version
	      print version information and exit.

Template format
       Each character in the template represents a character in the expanded filename, except for date	and  time  format  specifiers,	which  are
       replaced by their expansion.  Format specifiers consist of a `%' followed by one of the following characters:

       %      a literal % character

       n      a new-line character

       t      a horizontal tab character

       Time fields:

       H      hour (00..23)

       I      hour (01..12)

       p      the locale's AM or PM indicator

       M      minute (00..59)

       S      second (00..61, which allows for leap seconds)

       X      the locale's time representation (e.g.: "15:12:47")

       Z      time zone (e.g. GMT), or nothing if the time zone cannot be determined

       Date fields:

       a      the locale's abbreviated weekday name (e.g.: Sun..Sat)

       A      the locale's full weekday name (e.g.: Sunday .. Saturday)

       b      the locale's abbreviated month name (e.g.: Jan .. Dec)

       B      the locale's full month name, (e.g.: January .. December)

       c      the locale's date and time (e.g.: "Sun Dec 15 14:12:47 GMT 1996")

       d      day of month (01 .. 31)

       j      day of year (001 .. 366)

       m      month (01 .. 12)

       U      week of the year with Sunday as first day of week (00..53, where week 1 is the week containing the first Sunday of the year)

       W      week of the year with Monday as first day of week (00..53, where week 1 is the week containing the first Monday of the year)

       w      day of week (0 .. 6, where 0 corresponds to Sunday)

       x      locale's date representation (e.g. today in April in Britain: "13/04/97")

       y      year without the century (00 .. 99)

       Y      year with the century (1970 .. 2038)

       Other specifiers may be available depending on the C library's implementation of the strftime function.

SEE ALSO

       apache(1m) date(1) strftime(3) environ(5)

       More information and the latest version of cronolog can be obtained from

	       http://www.ford-mason.co.uk/resources/cronolog/

       If you have any suggestions, bug reports, fixes, or enhancements, please mail them to the author.

   More about Apache
       Documentation for the Apache http server is available from

	       http://www.apache.org

FUTURE DIRECTIONS

       The functionality of cronolog could be built into Apache, thus saving the overhead of having a process per log stream and that of transfer-
       ring data from the server process to the cronolog process.  The main complication is handling the case where multiple log streams are writ-
       ten to the same file (template), for example where different virtual servers write to the same set of log files.

AUTHOR

       Andrew Ford <A.Ford@ford-mason.co.uk>

       cronolog is based on a program called rotatelogs by Ben Laurie, which is packaged with the Apache web server.

       The symbolic link option was suggested by Juergen Lesny.

								    March 1998							      cronolog(1m)