This command creates a file "archivefile1.zip" which contains a copy of the files doc1, doc2, and doc3, located in the current directory.
zip archivefile1 doc1 doc2 doc3
This command creates a file "archivefile1.zip" which contains a copy of all files in the current directory in compressed form. However, files whose name starts with a "." are not included. The extension ".zip" is added by the program.
zip archivefile1 *
This version includes the files that start with a dot. But subdirectories are still not included.
zip archivefile1 .* *
This copies the current directory, including all subdirectories into the archive file.
zip -r archivefile1 .
This copies the directory "papers", located in the current directory, into "archivefile2.zip".
zip -r archivefile2 papers
This copies the directory "/home/joe/papers" into "archivefile3.zip". Since in this case the absolute path is given, it doesn't matter what the current directory is, except that the zip file will be created there.
zip -r archivefile3 /home/joe/papers
The command unzip extracts the files from the zip file.
This writes the files extracted from "archivefile1.zip" to the current directory.