When you enter McIDAS-X commands from the Unix prompt, a McIDAS environment is started and lasts only the duration of the command. For example, a separate McIDAS environment is started for each command below.
$ imgdisp.k GOES/HEMI.1000 1 $ frmsave.k 1 NHEM |
The command imgdisp.k loads the image in position 1000 of dataset GOES/HEMI into frame 1. When imgdisp.k is finished, the frame is deleted and the McIDAS environment closes. The Unix shell reads the next command, frmsave.k, and creates a new McIDAS environment and a new frame 1. The frmsave.k command saves the contents of frame 1 into the file NHEM.GIF. However, frame 1 is empty so NHEM.GIF is black except for the annotation line at the bottom.