The install of 7-zip includes a standalone command line version of the compression engine. Works great on Windows. Open source. Check the help file. The only file you need is 7za.exe.
Grab 7-zip from Sourceforge: http://sourceforge.net/projects/sevenzip/
(Includes a working recursive feature that works on Win - for some reason I just couldn't get InfoZip to recurse properly...)
"Unspecified Error" on right click context menu after upgrading a very old version of 7-zip (for Windows): What worked for me, uninstall, then rename the folder to break it (delete was blocked). The upgrade didn't clear out something in the folder, it seems.
tags: 7-zip, 7zip,