7-zip command line (7za) on OS X
The better solution to get 7-zip *command line* (7za) on an OS X installation
is to grab the p7zip (http://p7zip.sourceforge.net/) sources and compile them on a Mac (maybe Xcode is needed but not sure):
# working directory where p7zip sources are in is ./sources
tar xbfj p7zip_9.20_x86_linux_bin.tar.bz2
If all went fine in p7zip_9.20.1/bin there will what we need: the executable 7za.
p7zip is a port of 7za.exe for POSIX systems like Unix (Linux, Solaris, OpenBSD, FreeBSD, Cygwin, AIX, …), MacOS X and also for BeOS and Amiga.
7za.exe is the command line version of 7-zip, see http://www.7-zip.org/.
* source code got from http://sourceforge.net/projects/p7zip/
* executable built on OS X 10.8.5 (with both Xcode 4.5.1 and XCode 5.0 installed but – again – not sure whether Xcode is need)