All IRAF tasks are controlled by parameter sets edited by typing
epar tasknameFor example, to edit the task wfits type
epar wfitsand use the up and down arrows to position the cursor at different parameters. Merely type the desired parameter in followed by the return key to store the new value. Use Ctrl-Z or Ctrl-D (depending on the setup with obsinit) to save the new parameter set.
There are three parameter sets that control or modify the data taking process and should be modified to suit the observing needs. These parameter sets may be edited by just typing the name of the parameter set, unlike the discussion above.