If you can install hammer from git checkouts, you will just need rake installed on your system.
Clone and install CLI core
$ git clone https://github.com/theforeman/hammer-cli.git
$ cd hammer-cli
$ rake install
$ cd ..clone plugin with foreman commands
$ git clone https://github.com/theforeman/hammer-cli-foreman.git
$ cd hammer-cli-foreman
$ rake install
$ cd ..and optionally other plugins.
You'll have to copy configuration files to proper locations manually. Please check our configuration instructions and see how to proceed.