Fink provides hundreds of Open Source Unix tools compiled for OS X, free. Fink is an alternative to MacPorts. Some packages are available in only one package manager and some in both. You can use either or use both and install some packages with one tool and some with the other.
I have not used Fink in years: I do everything in MacPorts.
Here are instructions for setting up a 64-bit Fink, tested December 2012 with 10.8.2. When I switched to Mavericks in April 2014, Fink would not selfupdate, so I followed the instructions to delete all of Fink and reinstall. This worked OK. It kept asking me whether I wanted to install X and X11. I said no every time.
I used the "helper script" from the Fink page to reinstall Fink for OSX 10.10.4. The Fink update took hours. It kept hanging asking if I wanted XQuartz. I clicked "cancel" 16 times. When all the installation finished, fink said it was going to do "fink selfupdate" for the first time. This failed... apparently Fink installed Perl 5.18.3, and PERL5LIB was pointing at Perl 5.16.3. I think Fink also installed ANOTHER Java compiler. I was using Fink for only one program: I decided not to use it at all, and just use MacPorts.
Version 0.36.4 of Fink works on Mavericks (10.9). fink-0.38.0 was released on 18 October, 2014. The Fink Project announces official support for Yosemite (OS X 10.10) with the release of fink-0.38.0.
For Mountain Lion (10.8), see the Mountain Lion instructions on the Fink site.
Install Xcode Developer Tools first, including the correct version of the command line tools for your OS. You may also need to do sudo xcodebuild -license and enter agree.