Record a ssh log in Cygwin. Cygwin is slow on creating new process with `$( ... )`, so `tee` and add `$(date)` on each line would be extremely slow. run `sshlog` instead of `ssh`

add to .bashrc

  	function sshlog () {
		if [ "x$1" = "x" ]; then
		  echo "simple logging wrapper for ssh."
		  echo "use as usual ssh"
		  ssh
		else
		  TARGET=$1
		  mkdir -p ~/ssh-log
		  LOGFILE=~/ssh-log/$TARGET.$(date +%Y-%m-%d_%H.%M.%S).log
		  ssh $@ | python $HOME/timestamp-logger.py $LOGFILE
		  echo
		  echo "written log: $LOGFILE"
		  echo
		fi
		}

timestamp-logger.py

import sys, datetime
logfile = open(sys.argv[1], "w")
stdin = sys.stdin
print "writing log:", sys.argv[1]
while 1:
  try:
    c = stdin.read(1) 
    if not c:
      break
    sys.stdout.write(c)
    sys.stdout.flush()
    
    logfile.write(c)
    if c == "\n":
      logfile.flush()
      logfile.write(datetime.datetime.now().strftime("[%a %b %d %H:%M:%S.%f]"))
  except EOFError:
    break
logfile.close()