@ECHO OFF
 
REM Set default sock file
SET SSH_AUTH_SOCK=/tmp/ssh-agent.sock
 
REM Check socket is available
IF NOT EXIST "%TMP%\ssh-agent.sock" GOTO:RUNAGENT
 
REM Check if an ssh-agent is running
FOR /f "tokens=*" %%I IN ('ps ^| grep ssh-agent ^| sed "s/^ *\([0-9]\+\) .*/\1/"') DO SET VAR=%%I
IF "%VAR%" == "" GOTO:RUNAGENT
 
REM Check if socket file is valid
ssh-add -l 1> NUL 2>&1
IF ERRORLEVEL 1 GOTO:RUNAGENT
GOTO:ADDKEYS
 
:RUNAGENT
REM Remove old socket file
rm -f /tmp/ssh-agent.sock
 
REM Run ssh-agent and save (last) PID in VAR
SET VAR=
FOR /f "tokens=*" %%J IN ('ssh-agent -a /tmp/ssh-agent.sock') DO FOR /f "tokens=*" %%K IN ('echo %%J ^| grep "SSH_AGENT_PID" ^| sed "s/^SSH_AGENT_PID=\([0-9]\+\); .*/\1/"') DO SET VAR=%%K
 
:ADDKEYS
SET SSH_AUTH_PID=%VAR%
 
REM Check if ssh keys are known
SET KEYS=
FOR /f "tokens=*" %%I IN ('DIR /B "%HOME%\.ssh\*_rsa"') DO CALL:CHECKKEY %%I
 
REM Add missing ssh keys at once
IF NOT "%KEYS%" == "" ssh-add %KEYS%
GOTO:END
 
REM Functions
REM Check if ssh key has to be added
:CHECKKEY
SET VAR=
FOR /f "tokens=*" %%J IN ('ssh-add -l ^| grep "%1"') DO SET VAR=%%J
IF "%VAR%" == "" SET KEYS='%HOME%\.ssh\%1' %KEYS%
GOTO:EOF
 
:END
@ECHO ON