There are two possible styles for code examples. One is WYSIWYG as you type it on the Unix command line and in shell scripts:
% uvlist vis=cx012.SS433.2006sep07.1.miriad options=spectra
and the other employs the miriad shell, an AIPS like program in which you set variables and run the task, one by one. The output also shows all program parameters, leaving them blank if the default is used. These examples are not cut-and-paste friendly, but perhaps read a little easier.
Task: uvlist vis = cx012.SS433.2006sep07.1.miriad options = spectra select = line = scale = recnum = log =
Within the MIRIAD shell, the parameters are global, when you switch a taskname, the same vis= would appear in this list if the new task also has this parameter. This concept doesn't quite apply to the Unix command line.