This tmux wrapper is remarkably convenient:

Usage:

# Usage: t [session-name]
#
# With no arguments:
#   Lists existing tmux sessions, or prints "[No sessions]" if none exist.
#
# With a session name:
#   Attempts to attach to the named tmux session.
#   If the session does not exist, creates a new session with that name.
#
# Examples:
#   t            # Lists all tmux sessions
#   t dev        # Attaches to "dev" session or creates it if it doesn't exist

function t {
	if [[ -z $1 ]]; then
		tmux ls 2> /dev/null || echo "[No sessions]"
	else
		tmux attach -t $@ 2> /dev/null
		if [[ $? -ne 0 ]]; then
			tmux new -s $@
		fi
	fi
}