tt.py

#!/usr/bin/python2.7

from subprocess import check_output, STDOUT, CalledProcessError, call
from sys import argv, stdout, stdin

def run(func):
    """Run a function and capture the output."""
    if type(func) != type([]) and type(func) == type(""):
        func = func.split(' ')

    try:
        out = check_output(func, stderr=STDOUT)[:-1]
    except CalledProcessError as o:
        out = o.output[:-1]

    return out

ls = run('tmux ls')

if len(argv) == 1 and 'windows' in ls:
    print ls
    exit()

names = [i.split(":")[0]for i in ls.split("\n")]

if len(argv) == 1:
    argv = ['tt', '0']

if argv[1] in names:
    call(['tmux', 'attach', '-t', argv[1]])
    exit()

response = ''
while response != 'y':
    if not 'windows' in ls:
        out = 'no sessions, create one called "%s"? (y/n) '
    else:
        out = 'session "%s" does not exist, create it? (y/n) '
    stdout.write(out % argv[1])

    try:
        response = stdin.readline()[:-1].lower()
    except KeyboardInterrupt:
        exit()

    if response == 'y':
        call(['tmux', 'new-session', '-s', argv[1]])
    elif response == 'n':
        exit()