myshellconfig/bin/ssh-agent-start-or-restart

#!/bin/bash

[ -n "${SSH_AGENTS_DIR+x} ] && { AGENTS_DIR=${HOME}/.ssh/agents; export AGENTS_DIR; }
[ -n "${SSH_AGENT_SOCKETS_DIR+x} ] && { AGENTS_DIR=${HOME}/.ssh/agents; export AGENTS_DIR; }
agent-start-or-restart () {
    
    local ssh_identity
    local agentfile
    local agentsocket

    if [ -n "${1+x}" ]; then
        ssh_identity="$1"
        agentfile="${SSH_AGENTS_DIR}/agent-${ssh_identity}-$(hostname)"
        agentsocket="${SSH_AGENTS_SOCKETS_DIR}/socket-${ssh_identity}-$(hostname)"
        echo ssh-identität: $ssh_identity >&2
        if  [ -e $agentsocket ]; then

            /bin/sh -c ". $agentfile >/dev/null 2>&1; ssh-add -l >&2; exit $?"
            if [ $? -eq 2 ]; then
                echo "agent is not running" >&2
                rm "$agentsocket"
                ssh-agent -a $agentsocket > $agentfile 2>/dev/null
                echo "agent started" >&2
            else
                echo "agent is running" >&2
            fi
        else
                echo "agent is not running" >&2
                ssh-agent -a $agentsocket > $agentfile 2>/dev/null
                echo "agent startet" >&2

        fi
        echo -n "agent for $ssh_identity: " >&2
        echo $agentfile
        return 0
    else
        echo no identity given - exit >&2
        return 1
    fi


}


agent-start-or-restart $1
exit $?