NAME

       funhead - display a header in a Funtools file

SYNOPSIS

       funhead  [-a] [-s] [-t] [-L] <iname> [oname ename]

OPTIONS

         -a    # display all extension headers
         -s    # display 79 chars instead of 80 before the new-line
         -t    # prepend data type char to each line of output
         -L    # output in rdb/starbase list format

DESCRIPTION

       funhead displays the FITS header parameters in the specified FITS Extension.

       The first argument to the program specifies the Funtools input file to display.  If
       "stdin" is specified, data are read from the standard input. Funtools Bracket Notation is
       used to specify particular FITS extension to process.  Normally, the full 80 characters of
       each header card is output, followed by a new-line.

       If the -a switch is specified, the header from each FITS extensions in the file is
       displayed. Note, however, that the -a switch does not work with FITS files input via
       stdin. We hope to remove this restriction in a future release.

       If the -s switch is specified, only 79 characters are output before the new-line. This
       helps the display on 80 character terminals.

       If the -t switch is specified, the data type of the parameter is output as a one character
       prefix, followed by 77 characters of the param.  The parameter data types are defined as:
       FUN_PAR_UNKNOWN ('u'), FUN_PAR_COMMENT ('c'), FUN_PAR_LOGICAL ('l'), FUN_PAR_INTEGER
       ('i'), FUN_PAR_STRING ('s'), FUN_PAR_REAL ('r'), FUN_PAR_COMPLEX ('x').

       If the -L (rdb table) switch is used, the output will conform to starbase/rdb data base
       list format.

       For example to display the EVENTS extension (binary table):

         [sh] funhead "foo.fits[EVENTS]"
         XTENSION= 'BINTABLE'            /  FITS 3D BINARY TABLE
         BITPIX  =                    8  /  Binary data
         NAXIS   =                    2  /  Table is a matrix
         NAXIS1  =                   20  /  Width of table in bytes
         NAXIS2  =                30760  /  Number of entries in table
         PCOUNT  =                    0  /  Random parameter count
         GCOUNT  =                    1  /  Group count
         TFIELDS =                    7  /  Number of fields in each row
         EXTNAME = 'EVENTS  '            /  Table name
         EXTVER  =                    1  /  Version number of table
         TFORM1  = '1I      '            /  Data type for field
         TTYPE1  = 'X       '            /  Label for field
         TUNIT1  = '        '            /  Physical units for field
         TFORM2  = '1I      '            /  Data type for field
           etc. ...
         END

       To display the third header:

         [sh] funhead "foo.fits[3]"
         XTENSION= 'BINTABLE'            /  FITS 3D BINARY TABLE
         BITPIX  =                    8  /  Binary data
         NAXIS   =                    2  /  Table is a matrix
         NAXIS1  =                   32  /  Width of table in bytes
         NAXIS2  =                   40  /  Number of entries in table
         PCOUNT  =                    0  /  Random parameter count
         GCOUNT  =                    1  /  Group count
         TFIELDS =                    7  /  Number of fields in each row
         EXTNAME = 'TGR     '            /  Table name
         EXTVER  =                    1  /  Version number of table
         TFORM1  = '1D      '            /  Data type for field
           etc. ...
         END

       To display the primary header (i.e., extension 0):

         sh> funhead "coma.fits[0]"
         SIMPLE  =                    T /STANDARD FITS FORMAT
         BITPIX  =                   16 /2-BYTE TWOS-COMPL INTEGER
         NAXIS   =                    2 /NUMBER OF AXES
         NAXIS1  =                  800 /
         NAXIS2  =                  800 /
         DATATYPE= 'INTEGER*2'          /SHORT INTEGER
         END

       The funhead program also can edit (i.e. add, delete, or modify) or display individual
       headers parameters. Edit mode is signalled by the presence of two additional command-line
       arguments: output file and edit command file, in that order. Edit mode acts as a filter:
       the output file will contain the entire input FITS file, including other extensions. The
       edit command file can be "stdin", in which case edit command are read from the standard
       input.

       The edit command file contains parameter comments (having '#' in the first column) and
       delete and assignment(modify or add) operations.  A delete operation is specified by
       preceding the parameter name with a minus sign "-".  A display operation (very useful in
       interactive sessions, i.e., where the edit commands are taken from stdin) is specified by
       preceding the parameter name with a question mark "?". In either case, a parameter value
       need not be specified.  An assignment operation is specified in the same two ways that a
       parameter is specified in a text header (but without the comment character that precedes
       header params), i.e.:

       •   FITS-style comments have an equal sign "=" between the keyword and value and an
           optional slash "/" to signify a comment. The strict FITS rules on column positions are
           not enforced.

       •   Free-form comments can have an optional colon separator between the keyword and value.
           In the absence of quote, all tokens after the keyword are part of the value, i.e. no
           comment is allowed.

       For example, the following interactive session checks for the existence of parameters,
       adds new parameters, modifies them, and modifies and deletes existing parameters:

         sh$ ./funhead snr.ev foo.fits -
         # look for FOO1
         ? FOO1
         WARNING: FOO1 not found
         # add new foo1
         FOO1 = 100
         # add foo2
         FOO2 = 200
         # reset foo1 to a different value
         FOO1 -1
         # delete foo2
         -FOO2
         # change existing value
         EXTVER 2
         ? XS-SORT
         XS-SORT = 'EOF     '            /  type of event sort
         # delete existing value
         -XS-SORT
         # exit
         ^D

       See Column-based Text Files for more information about header parameter format.

SEE ALSO

       See funtools(7) for a list of Funtools help pages