DESCRIPTION

       It  is  sometimes  convenient to maintain text files on the system with
       non-standard tabs, (tabs that are not  set  at  every  eighth  column).
       Such files must generally be converted to a standard format, frequently
       by replacing all tabs with the appropriate  number  of  spaces,  before
       they  can  be  processed  by  system  commands.  A format specification
       occurring in the first line of a text file specifies how tabs are to be
       expanded in the remainder of the file.

       A  format  specification consists of a sequence of parameters separated
       by blanks and surrounded by the brackets <:  and  :>.   Each  parameter
       consists of a keyletter, possibly followed immediately by a value.  The
       following parameters are recognized:

         ttabs     The t parameter specifies the tab settings  for  the  file.
                   The value of tabs must be one of the following:

                   1.     A  list of column numbers separated by commas, indi-
                          cating tabs set at the specified columns.

                   2.     A '-' followed immediately by an integer n, indicat-
                          ing tabs at intervals of n columns.

                   3.     A '-' followed by the name of a ``canned'' tab spec-
                          ification.

                   Standard  tabs  are  specified  by  t-8,  or  equivalently,
                   t1,9,17,25,  etc.   The canned tabs that are recognized are
                   defined by the tabs(1) command.

         ssize     The s parameter specifies a maximum line size.   The  value
                   of  size  must  be  an integer.  Size checking is performed
                   after tabs have been expanded, but  before  the  margin  is
                   prepended.

         mmargin   The  m  parameter  specifies  a  number  of  spaces  to  be
                   prepended to each line.  The value of  margin  must  be  an
                   integer.

         d         The  d  parameter  takes  no value.  Its presence indicates
                   that the line containing the format specification is to  be
                   deleted from the converted file.

         e         The  e  parameter  takes  no value.  Its presence indicates
                   that the current format is to prevail  only  until  another
                   format specification is encountered in the file.

       Default  values, which are assumed for parameters not supplied, are t-8
       and m0.  If the s parameter is not specified, no size checking is  per-
       formed.  If the first line of a file does not contain a format specifi-
       cation, the above defaults are assumed for the entire file.   The  fol-
       lowing is an example of a line containing a format specification: