Could you help me please to find the reason why the pset4.zip doesn't unzip and the command line shows the following error instead?
jharvard@appliance (~): unzip pset4.zip Archive: pset4.zip End-of-central-directory signature not found. Either this file is not a zipfile, or it constitutes one disk of a multi-part archive. In the latter case the central directory and zipfile comment will be found on the last disk(s) of this archive. unzip: cannot find zipfile directory in one of pset4.zip or pset4.zip.zip, and cannot find pset4.zip.ZIP, period.