When adding new file access programs, analysis routines, and scale programs, SAOtng will macro-expand your command line before executing it. This is one way in which SAOtng's internal information can be supplied to external programs. Macros are of the form $macro or ${macro}: the same format used for Unix shell variables. SAOtng knows about several classes of macros:

Reserved macros

The following words are reserved as macros:

• filename, imgpath -- pathname of the original image file
• imgname -- file name of the image file (w/o path)
• imgroot -- root name of the image file (w/o path or extension)
• xdim, ydim -- dimensions of the current image section
• xcen ycen -- center of image at which section was extracted
• block -- block factor at which section was extracted
• min, max -- min and max data value of image section

Data keywords

The macro expands in such a way as to make the raw (unscaled) FITS data representation of the image section available in way suitable for use in a Unix pipe or to be redirected into a file. For example, a command line such as:

    $data | smooth fits="stdin" ...

will send the raw data into the standard input of a smooth program, while:

    $data > foo.fit; smooth fits=foo.fit ...

redirects the raw data into a file and then passes the file to a smooth program. The $data macro will expand to an xpaget of the unscaled FITS image from memory, if such data is available. If not, it will expand to a command to retrieve the appropriate FITS image section from the original image file.

FITS keywords

All keywords contained in the primary FITS header can be expanded as macros on a command line.

Region keywords

The following region keywords are defined when launching analysis routines:

• region, regions -- all regions
• exclude_region, exclude_regions -- exclude regions
• eregion, eregions -- exclude regions
• include_region, include_regions -- include regions
• iregion, iregions -- include regions

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Last Updated May 1, 1995