Resolving dependencies fails on Ubuntu 12.04 LTS

I’m running a standard Ubuntu 12.04 LTS server, no self-compiled software and no hacks, just the original Ubuntu-packages. Since there is no letsencrypt package available I pulled everything out of git according to https://letsencrypt.org/howitworks/ and then did a ./letsencrypt-auto (and ./letsencrypt-auto --help). This starts getting some packages but fails with “virtualenv” and “git” being unresolved dependencies.

virtualenv is indeed no Ubuntu 12.04 package, and git is named “git-core”, not “git”.

So…how can one use letsencrypt on Ubuntu 12.04? Since it is an LTS version it is far away from being outdated.

There are a number of other clients - List of Client Implementations
is it looking for “virtualenv” ? or python-virtualenv ?

It is looking for a package “virtualenv”.