summary

summary needs a minimum of two arguments. First is smspec filename and then list of vectors

In addition, the program takes these options (which must be given before the arguments):

-h Print help and exit. -l list all summary vectors. -r extract data only for report steps.

The full documentation for summary is maintained as a Texinfo manual. If the info and summary programs are properly installed at your site, the command

info summary

should give you access to the complete manual.