ssh-agent script for git on windows

For the past week I've been back in Windows to do some embedded development and I couldn't stand having to type in my passwords when for contacting git repos and updating submodules.

MySysGit doesn't come with ssh-copy-id, but this script I found at http://gabrielsomoza.com/server-administration/ssh-copy-id-implementation-for-mingw-and-msys/ works every bit as well.

	#!/bin/sh
	usage () {
	echo "Usage: $0 [-i [identity_file]] [user@]machine"
	exit 1
	}
	# Parse options
	while getopts ":i:" o
	do case "$o" in
	i) # Identity file specified
	if [ $(($OPTIND-1)) -eq $# ] # if there's no other argument after this one
	then
	# Make sure last argument is not a file or folder to catch this case where no host is provided:
	# ssh-copy-id -i [identity_file]
	[ ! -f "$OPTARG" ] || usage
	[ ! -d "$OPTARG" ] || usage
	# If last argument is not a file, read the default key and continue
	key=`cat "$HOME/.ssh/id_rsa.pub"` #
	else # read specified identity
	[ -f "$OPTARG" ] || usage
	key=`cat "$OPTARG"`
	fi;;
	[?]) usage;;
	esac
	done
	[ $# -gt 0 ] || usage
	shift $(($# - 1))
	# Show usage if no host given
	host=$1
	if [ -z "$host" ]
	then
	usage
	fi
	# Default to `ssh-add -L` if no -i option given
	if [ -z "$key" ]
	then
	key=`ssh-add -L`
	fi
	echo "Uploading private key..."
	ssh $host 'mkdir -pm 700 ~/.ssh; echo ' $key ' >> ~/.ssh/authorized_keys ; chmod 600 ~/.ssh/authorized_keys'
	echo "Done."
	exit 0

view raw ssh-copy-id.sh hosted with ❤ by GitHub

Then to get an agent to keep those keys available there's this little script somewhat hidden in a github help page: https://help.github.com/articles/working-with-ssh-key-passphrases

I call it from my .profile and it works like a charm, asking for my key's passphrase just once when I launch my first mingw shell.

SSH_ENV="$HOME/.ssh/environment"

# start the ssh-agent
function start_agent {
    echo "Initializing new SSH agent..."
    # spawn ssh-agent
    ssh-agent | sed 's/^echo/#echo/' > "$SSH_ENV"
    echo succeeded
    chmod 600 "$SSH_ENV"
    . "$SSH_ENV" > /dev/null
    ssh-add
}

# test for identities
function test_identities {
    # test whether standard identities have been added to the agent already
    ssh-add -l | grep "The agent has no identities" > /dev/null
    if [ $? -eq 0 ]; then
        ssh-add
        # $SSH_AUTH_SOCK broken so we start a new proper agent
        if [ $? -eq 2 ];then
            start_agent
        fi
    fi
}

# check for running ssh-agent with proper $SSH_AGENT_PID
if [ -n "$SSH_AGENT_PID" ]; then
    ps -ef | grep "$SSH_AGENT_PID" | grep ssh-agent > /dev/null
    if [ $? -eq 0 ]; then
  test_identities
    fi
# if $SSH_AGENT_PID is not properly set, we might be able to load one from
# $SSH_ENV
else
    if [ -f "$SSH_ENV" ]; then
  . "$SSH_ENV" > /dev/null
    fi
    ps -ef | grep "$SSH_AGENT_PID" | grep ssh-agent > /dev/null
    if [ $? -eq 0 ]; then
        test_identities
    else
        start_agent
    fi
fi