FSPEC(4)                                                              FSPEC(4)


NAME
     fspec - format specification in text files

DESCRIPTION
     It is sometimes convenient to maintain text files on the UNIX system with
     non-standard tabs, (i.e., tabs which 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 UNIX 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, indicating
                     tabs set at the specified columns;

                  2. a - followed immediately by an integer n, indicating tabs
                     at intervals of n columns;

                  3. a - followed by the name of a ``canned'' tab
                     specification.

                Standard tabs are specified by t-8, or equivalently,
                t1,9,17,25,etc.  The canned tabs which 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
     performed.  If the first line of a file does not contain a format
     specification, the above defaults are assumed for the entire file.  The


     following is an example of a line containing a format specification:

           * <:t5,10,15 s72:> *

     If a format specification can be disguised as a comment, it is not
     necessary to code the d parameter.

SEE ALSO
     ed(1), newform(1), tabs(1)


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