我在python中使用子进程拒绝了Errno 13 Permission

ret=subprocess.call(shlex.split(cmd))

cmd = /usr/share/java -cp pig-hadoop-conf-Simpsons:lib/pig-0.8.1-cdh3u1-core.jar:lib/hadoop-core-0.20.2-cdh3u1.jar org.apache.pig.Main -param func=cat -param from =foo.txt -x mapreduce fsFunc.pig

错误是.

File "./run_pig.py",line 157,in process
    ret=subprocess.call(shlex.split(cmd))
File "/usr/lib/python2.7/subprocess.py",line 493,in call
  return Popen(*popenargs,**kwargs).wait()
File "/usr/lib/python2.7/subprocess.py",line 679,in __init__
  errread,errwrite)
File "/usr/lib/python2.7/subprocess.py",line 1249,in _execute_child
  raise child_exception
OSError: [Errno 13] Permission denied

如果需要更多信息,请告诉我.任何帮助表示赞赏.谢谢.