Use a HTTP proxy to connect to a SSH server (and GIT)

Install socat, i.e. with centos :

  sudo yum install socat

Create a user config file ~/.ssh/config :

Host host-git
  ProxyCommand  socat - PROXY:<proxy ip/host>:%h:%p,proxyport=<proxy port>

Change permission on this new file :

chmod 600 ~/.ssh/config

Then for GIT, you can then edit git's config file <REPO>/.git/config and modify remote section

[remote "origin"]
        #url = https://[email protected]/chemin-du-repo.git
        url = ssh://user-git@host-git/chemin-du-repo.git

...or if you do not already have a remote origin add it :

git remote add origin ssh://user-git@host-git/chemin-du-repo.git

and then push your modifications :

git push -u origin master