NAME

       mhical - nmh's manipulator of iCalendar event requests

SYNOPSIS

       mhical [-help] [-version] [-form formatfile] [-format formatstring] [[-reply accept |
            decline | tentative] | -cancel] [-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.

   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), 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.