screen -lsの出力を見て適切にオプションつけてscreenを起動してくれるスクリプト

myscreen.sh

#!/bin/bash

STATUS=`screen -ls`

new_session() {
  exec screen
}

detach_and_reattach() {
  exec screen -d -r
}

multi_attach() {
  exec screen -x
}

reattach() {
  exec screen -r
}

echo $STATUS | grep 'No Sockets found' > /dev/null 2>&1
if [ $? -eq 0 ]; then
  new_session
  exit 0
fi

echo $STATUS | grep '1 Socket in' > /dev/null 2>&1
if [ $? -eq 0 ]; then

  echo $STATUS | grep 'Attached' > /dev/null 2>&1
  if [ $? -eq 0 ]; then
    multi_attach
    exit 0
  fi

  echo $STATUS | grep 'Detached' > /dev/null 2>&1
  if [ $? -eq 0 ]; then
    reattach
    exit 0
  fi

  echo '[ERROR] parse `screen -ls` error.'
  echo "$STATUS"
  exit 1
fi

echo '[WARN] more than 1 session found. Please reconnect manually.'
echo "$STATUS"
exit 1