run multiple command line with subprocess
def subprocess_cmd(command):
process = subprocess.Popen(command,stdout=subprocess.PIPE, shell=True)
proc_stdout = process.communicate()[0].strip()
print proc_stdout
subprocess_cmd('echo a; echo b')
# example single command
subprocess.Popen('rosrun topic_tools mux cmd_vel auto_cmd_vel manual_cmd_vel mux:=mux_cmd_vel', shell= True)