Many VISTA commands read from or write to the disk, and therefore require filenames. The program has defined several default directories and extensions for the various types of files that VISTA uses: for example, images are stored in one directory, spectra in a second, procedures in a third, etc. Unless you specify otherwise, VISTA will automatically search in certain directories for images, spectra, etc., and will assume that the files have standard extensions. You can view these default directories with the VISTA command PRINT DIRECTORIES.
An example of a default directory is this: The WD command writes an image
to disk with a filename specified in the command. Assume the default
directory for images is /vista/ccd/ and the default file extension for
images is .CCD. The command
The default directories are established when the VISTA program is run by a
subroutine called INITIAL. That subroutine has a standard list of
directories and extensions that it loads into a common block for use by
other subroutines. The default directories can be changed by the user in
two ways:
An example is:
writes the image in buffer 2 to the file /vista/ccd/m15.fits You can
override the default locations any time: for example
Variable
Directory for
V_CCDIR
Images
V_PRODIR
Procedures
V_SPECDIR
Spectra
V_FLUXDIR
Flux calibrations
V_LAMBDIR
Wavelength calibrations
V_COLORDIR
TV color files
V_DATADIR
Data files.
V_DAODIR
DAOPHOT files.
Remember, you must execute these setenv commands BEFORE starting VISTA.