この記事( https://help.github.com/articles/working-with-ssh-key-passphrases )のスクリプトを改良してみました。

これでconfigを置いていてもssh-addが動くはず。

会社ではMysysGitとCygwin上で自分でコンパイルしたGitのために使っています。

普通にSSH使う場合も便利かもしれない。

※複数のHostで使うキーをConfigに指定していた場合不具合を修正しました。

# ! /bin/bash

SSH_CONFIG="$HOME/.ssh/config"
SSH_ENV="$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
    add_key
    if [ $? -ne 0 ]; then
        echo "[Error] Fail to add_key..."
        stop_agent
        return 1
    fi
}

function stop_agent {
    ps -f -u $USERNAME | grep "$SSH_AGENT_PID" | grep ssh-agent > /dev/null
    if [ $? -ne 0 ]; then
       return 1
    fi
    echo "Stop Agent..."
    echo "PID:$SSH_AGENT_PID"
    rm $SSH_ENV
    kill $SSH_AGENT_PID
    SSH_AGENT_PID=
    return 0
}

function add_key {
    echo "Adding keys."
    local ssh_add_cmd=""
    if [ -f "$SSH_CONFIG" ]; then
        echo "Search config"
        ssh_add_cmd=`cat $SSH_CONFIG |
                     grep "IdentityFile" |
                     sed -e "s/IdentityFile/ssh-add/g ;
                             s/[ 	]\+/ /g ;
                             s/ ~/ ${HOME//\//\\/}/"`
    fi

    if [ "$ssh_add_cmd" = "" ]; then
      echo "ssh-add with default keys."
      ssh-add
      if [ $? -ne 0 ]; then
          return 1
      fi
      return 0
    else
      echo "config found. ssh-add with your setting keys."
      echo $ssh_add_cmd | bash
      return 0
    fi
    return 1
}

# 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
        add_key
        # $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 -f -u $USERNAME | grep "$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 -f -u $USERNAME | grep "$SSH_AGENT_PID" | grep ssh-agent > /dev/null
    if [ $? -eq 0 ]; then
        test_identities
    else
        start_agent
    fi
fi