tmux conf one session multiple windows

sample_tmux.conf

#!/bin/bash

tmux start-server
dev_session_name="dev"

tmux has-session -t $dev_session_name
if (( $? )) ; then
	tmux new-session -d -s ${dev_session_name} -n src
	tmux send-keys "ses 0 command" C-m 

	tmux new-window -t ${dev_session_name}:1 -n sblock
	tmux send-keys "ses 1 command" C-m 

	tmux new-window -t ${dev_session_name}:2 -n shal
	tmux send-keys "ses 2 command" C-m 
else
	echo "dev session already exist"
fi

tmux attach-session -t ${dev_session_name}