To install the "zip" and "unzip" command under Windows able to run from command 
line, it is required to download the .exe files that perform the commands and add 
the path of these files to the Path system variable. To do it, perform the following steps:

1. download .exe files of the utilities at the following links
"zip" utility: http://stahlworks.com/dev/zip.exe
"unzip" utility: http://stahlworks.com/dev/unzip.exe

2. create a folder in C:\ProgrammFiles (admin privileges required) and name it "CompressionUtilities"

3. move the downloaded files in the created folder

3. open the System Panel: ControlPanel -> System and Security -> System

4. on the left side, click on Advanced system settings

5. click on Environmental Variables

6. in the lower part of the window (System variables), scroll until you find the Variable "Path"

7. click on it, then click on "Edit..."

8. reach the end of the string and append the following (don't copy the quotes, just what is inside): ";C:\Program Files\CompressionUtilities"
		ATTENTION: DO NOT delete the existing string, just append this path to the others

9. click on "ok" and "ok again"

10. open a prompt window and type "zip" or "unzip" that now should prompt with the usage hints