NAME

       mhical - nmh's manipulator of iCalendar event requests

SYNOPSIS

       mhical [-help] [-version] [-form formatfile] [-format formatstring] [[-reply accept | decline |
            tentative] | -cancel] [-attendee address] [-contenttype] [-infile infile] [-outfile outfile]
            [-unfold] [-debug]

DESCRIPTION

       mhical  manipulates  an  iCalendar (.ics) event request, to display it, generate a reply to it, or cancel
       it.  iCalendar event requests and replies are defined by RFC 5545.

       The default operation is to display the iCalendar event request in a human-readable format.

       For the display operation, the -format string and -form formatfile switches may  be  used  to  specify  a
       format  string  or  a  format  file  to read.  If given a format string, it must be specified as a single
       argument to the -format switch.  If given a format file name with -form, the file is searched  for  using
       the normal nmh rules: absolute pathnames are accessed directly, tilde expansion is done on usernames, and
       files are searched for in the user's Mail directory as specified in their profile.  If not  found  there,
       the  directory  “/etc/nmh”  is  checked.  mhical defaults to using a format file named mhical.24hour, and
       will use the one installed in the “/etc/nmh” directory if not found elsewhere.

       The following format components are supported:

            method
            organizer
            summary
            description
            location
            dtstart
            dtend
            attendees

       Those format names are case-sensitive.  Each corresponds to the iCalendar property of the  same  name  as
       defined  in RFC 5545, with the exception of attendees.  That is a comma-delimited list of the common name
       (CN), if available, or email address of Attendee properties.  A maximum of 20 will be displayed.

   Timezone
       mhical will display the event with times converted to  the  timezone  specified  by  the  TZ  environment
       variable,  if  it  is set, see tzset(3).  If not set, its behavior is implementation defined, but may use
       the user's local timezone.

   Reply
       The -reply switch generates a reply from the event request.  The required action parameter must be one of
       accept, decline, or tentative.  Delegation is not supported.

       If one of your mailboxes matches more than one attendee in the request, the -attendee switch must be used
       to select the one to use in the reply.  The -attendee switch can also be used  to  specify  the  attendee
       address if no attendees match any of your mailboxes.

   Cancel
       The -cancel switch generates an iCalendar event that can be used to cancel the event request.

   Input/Output
       By  default,  mhical  reads from standard input and writes to standard output.  The -infile and -outfile,
       respectively, switches can be used to override these defaults.

   Miscellaneous Switches
       The -contenttype switch instructs mhical to insert a Content-Type header at the beginning of its  output,
       for use by mhbuild.  It can only be used with -reply and -cancel.

       The -unfold switch echoes the event request, but with all lines unfolded.

       The -debug switch reveals minute details of the parse process.

FILES

       mhical  looks  for  format  files in multiple locations:  absolute pathnames are accessed directly, tilde
       expansion is done on usernames, and files are searched for in the user's Mail directory as  specified  in
       their profile.  If not found there, the directory “/etc/nmh” is checked.

       /etc/nmh/mhical.24hour  The default display template
       /etc/nmh/mhical.12hour  Display template that uses 12-hour clock

SEE ALSO

       mhbuild(1), mh-format(5), mh-profile(5), tzset(3), repl(1)

DEFAULTS

       `-form' defaults to mhical.24hour
       `-infile' defaults to standard input
       `-outfile' defaults to standard output

BUGS

       mhical  supports  only  a very limited subset of RRULE formats.  Specifically, only a frequency of YEARLY
       and an interval of 1 are supported.

       mhical produces output with just newlines instead  of  carriage  return-newline  combinations.   This  is
       intentional, to fit with typical nmh convention.