For macOS/OS X 10.9 and higher, install Git for Mac
by downloading and running the most recent "mavericks" installer from
this list.
After installing Git, there will not be anything in your /Applications
folder,
as Git is a command line program.
For older versions of OS X (10.5-10.8) use the
most recent available installer labelled "snow-leopard"
available here.
If Git is not already available on your machine you can try to
install it via your distro's package manager. For Debian/Ubuntu run
sudo apt-get install git
and for Fedora run
sudo yum install git
.