As of this writing, mosh in EPEL is broken in terms of install on Amazon Linux (2013-03). However, that doesn't mean you can't just build it manually.

First, you will need git:

sudo yum install git

Open /etc/yum.repos.d/epel.repo and change enabled=0 to enabled=1 in the [epel] section.

Install all the dependencies necessary to build mosh:

sudo yum install protobuf-compiler protobuf-devel libutempter-devel \
    ncurses ncurses-devel zlib-devel autoconf automake openssl-devel \
    gcc gcc-c++

First you need to clone the mosh source using git. We'll do all our work in /var/tmp:

cd /var/tmp
git clone https://github.com/keithw/mosh.git
cd mosh

You should now be in /var/tmp/mosh, or whatever directory you cloned mosh into. Run the following commands:

./autogen.sh
./configure
make
sudo make install

You should be all set now. Note that unless you change configure options, mosh will be installed in /usr/local/bin by default. You can change that with the standard –prefix option.

If you run into any errors, please let me know via email at admin at splitstreams dot com.