ssh-wrapper - for use with https://gist.github.com/1004653 (buildhuman script)

gistfile1.bash

#!/bin/sh

# ssh-wrapper :: helper script for git to run custom ssh commands
#
# example usage:
#   GIT_SSH=ssh-wrapper GIT_SSH_KEY=my_private_key.rsa git ...

if [ -s "$GIT_SSH_KEY" ]; then
    exec ssh -i "$GIT_SSH_KEY" "$@"
else
    exec ssh "$@"
fi