1.4.1 Obtaining a Directory Listing

 Identifying the IUE images which are loaded in your disk area can be done in several ways on the IUE Vax, as shown in Table 1.5. There is an IDL library procedure (DIR) which will execute the VMS command DIRECTORY. You may execute VMS commands (e.g., DIR/SIZE) from within IDL by preceding them with a dollar sign or by using the SPAWN procedure. Users on UNIX systems may execute UNIX commands (e.g., ls) in a similar way.

 

 

Table 1.5: Obtaining Directory Listings

Expression	Definition
DIR	Lists all files.
DIR,'*.lab'	Lists all files with .LAB extension.
$ DSD	Lists all files along with creation date and file size.
filelist=FINDFILE('file_specification')	Generates string array containing list of all files meeting the file specification.
LIST=FINDFILE('$\ast$H.LAB')	Find all label files for IUE high dispersion spectral data, and place them in the string array called LIST.
SPAWN,'DIR'	IDL procedure to execute the VMS directory command.
SPAWN,'ls'	Analogous command to execute ls on UNIX systems.