python执行系统命令后获取返回值的几种方式集合

os.system('ps aux') 

result = os.popen('ps aux') 
   res = result.read() 
   for line in res.splitlines(): 
       print line 

p = subprocess.Popen('ps aux',shell=True,stdout=subprocess.PIPE) 
  out,err = p.communicate() 
  for line in out.splitlines(): 
    print line 

output = commands.getstatusoutput('ps aux') 
print output