ssh-agent automation done well

joseph_reagle.bash

SSH_ENV="$HOME/.ssh/environment"

function start_agent {
     echo "Initialising new SSH agent..."
     /usr/bin/ssh-agent | sed 's/^echo/#echo/' > "${SSH_ENV}"
     echo succeeded
     chmod 600 "${SSH_ENV}"
     . "${SSH_ENV}" > /dev/null
     /usr/bin/ssh-add;
}

# Source SSH settings, if applicable

if [ -f "${SSH_ENV}" ]; then
     . "${SSH_ENV}" > /dev/null
     #ps ${SSH_AGENT_PID} doesn't work under cywgin
     ps -ef | grep ${SSH_AGENT_PID} | grep ssh-agent$ > /dev/null || {
         start_agent;
     }
else
     start_agent;
fi

kyle_amon.bash

#
# setup ssh-agent
#


# set environment variables if user's agent already exists
[ -z "$SSH_AUTH_SOCK" ] && SSH_AUTH_SOCK=$(ls -l /tmp/ssh-*/agent.* 2> /dev/null | grep $(whoami) | awk '{print $9}')
[ -z "$SSH_AGENT_PID" -a -z `echo $SSH_AUTH_SOCK | cut -d. -f2` ] && SSH_AGENT_PID=$((`echo $SSH_AUTH_SOCK | cut -d. -f2` + 1))
[ -n "$SSH_AUTH_SOCK" ] && export SSH_AUTH_SOCK
[ -n "$SSH_AGENT_PID" ] && export SSH_AGENT_PID

# start agent if necessary
if [ -z $SSH_AGENT_PID ] && [ -z $SSH_TTY ]; then  # if no agent & not in ssh
  eval `ssh-agent -s` > /dev/null
fi

# setup addition of keys when needed
if [ -z "$SSH_TTY" ] ; then                     # if not using ssh
  ssh-add -l > /dev/null                        # check for keys
  if [ $? -ne 0 ] ; then
    alias ssh='ssh-add -l > /dev/null || ssh-add && unalias ssh ; ssh'
    if [ -f "/usr/lib/ssh/x11-ssh-askpass" ] ; then
      SSH_ASKPASS="/usr/lib/ssh/x11-ssh-askpass" ; export SSH_ASKPASS
    fi
  fi
fi

ssh_agent_kill.fish

# ~/.config/fish/conf.d/z-ssh_agent_kill.fish
function ssh_agent_kill --on-event fish_exit
    if [ -n "$SSH_AGENT_PID" ]
        ssh-add -D
        ssh-agent -k
    end
end

ssh_agent_start.fish

# ~/.config/fish/functions/ssh_agent_start.fish
function ssh_agent_start
  set -l agents (find $TMPDIR -iname 'agent.*' -user (whoami))
  if [ count $agents -eq 0 ]
    eval (ssh-agent -c)
    ssh-add $HOME/.ssh/* # bad practice, yet convenient
  else if [ -z "$SSH_AUTH_SOCK" -o -z "$SSH_AGENT_PID" ]
    setenv SSH_AUTH_SOCK $agents[1]
    setenv SSH_AGENT_PID (math 1 + (echo $SSH_AUTH_SOCK | cut -d. -f2))
  end
end

# ~/.config/fish/functions/ssh_agent_start_env.fish
function ssh_agent_start_env
  set -q SSH_ENV
  if [ $status -ne 0 ]
    set -gx SSH_ENV "$HOME/.ssh/environment"
  end
  if [ ! -s $SSH_ENV ]
    ssh-agent -c | sed '/^echo/d' > $SSH_ENV
    chmod 600 $SSH_ENV
  end
  . $SSH_ENV
end

# ~/.config/fish/config.fish
set -gx SSH_ENV "$HOME/.ssh/environment"