NAME

       cron - Tool for automating the period callback of commands

SYNOPSIS

       package require Tcl  8.5

       package require cron  ?0.1?

       ::cron::at ?processname? timecode command

       ::cron::cancel processname

       ::cron::every processname frequency command

       ::cron::in ?processname? timecode command

________________________________________________________________________________________________________________

DESCRIPTION

       The cron package provides a Pure-tcl set of tools to allow programs to schedule tasks to occur at regular
       intervals.  Rather  than force each task to issue it's own call to the event loop, the cron system mimics
       the cron utility in Unix: on task periodically checks to see if something is to be done, and  issues  all
       commands for a given time step at once.  The cron package is intended to work in time scales greater than
       1 second.

COMMANDS

       ::cron::at ?processname? timecode command
              This  command  registers a command to be called at the time specified by timecode.  If timecode is
              expressed as an integer, the timecode is assumed to be in  unixtime.  All  other  inputs  will  be
              interpreted  by  clock  scan  and converted to unix time.  This task can be modified by subsequent
              calls to this package's commands by referencing processname. If processname  exists,  it  will  be
              replaced.  If processname is not given, one is generated and returned by the command.

              ::cron::at start_coffee {Tomorrow at 9:00am}  {remote::exec::coffeepot power on}
              ::cron::at shutdown_coffee {Tomorrow at 12:00pm}  {remote::exec::coffeepot power off}

       ::cron::cancel processname
              This  command  unregisters  the  process  processname  and  cancels  any  pending commands.  Note:
              processname can be a process created by either ::cron::at or ::cron::every.

              ::cron::cancel check_mail

       ::cron::every processname frequency command
              This command registers a command to be called at the interval of frequency.  frequency is given in
              seconds. This task can be modified by subsequent calls to this package's commands  by  referencing
              processname. If processname exists, it will be replaced.

              ::cron::every check_mail 900  ::imap_client::check_mail
              ::cron::every backup_db  3600 {::backup_procedure ::mydb}

       ::cron::in ?processname? timecode command
              This  command  registers  a  command  to  be  called  after a delay of time specified by timecode.
              timecode is expressed as an seconds.  This task can  be  modified  by  subsequent  calls  to  this
              package's  commands  by  referencing  processname. If processname exists, it will be replaced.  If
              processname is not given, one is generated and returned by the command.

BUGS, IDEAS, FEEDBACK

       This document, and the package it describes, will undoubtedly contain bugs and  other  problems.   Please
       report  such  in the category odie of the Tcllib Trackers [http://core.tcl.tk/tcllib/reportlist].  Please
       also report any ideas for enhancements you may have for either package and/or documentation.

KEYWORDS

       cron, odie

CATEGORY

       System

COPYRIGHT

       Copyright (c) 2015 Sean Woods <yoda@etoyoc.com>

tcllib                                                 0.1                                            cron(3tcl)