Popen error: [Errno 2] No such file or directory

问题:

I have some custom commands.

# works 
subprocess.Popen(['python'], stdout=subprocess.PIPE)

But if I have my own system commands like deactivate, I get that error

Traceback (most recent call last):
  File "runner2.py", line 21, in <module>
    main() 
  File "runner2.py", line 18, in main
    subprocess.Popen(['deactivate',], stdout=subprocess.PIPE)
  File "/usr/lib/python2.6/subprocess.py", line 633, in __init__
    errread, errwrite)
  File "/usr/lib/python2.6/subprocess.py", line 1139, in _execute_child
    raise child_exception
OSError: [Errno 2] No such file or directory

Let alone I need to execute this under my sandbox virtualenv.

回答1:

Try add an extra parameter 'shell=True' to the Popen call.

回答2:

Just a note. shell=True was likely the correct solution to the o.p., since they did not make the following mistake, but you can also get the "No such file or directory" error if you do not split up your executable from its arguments.

import subprocess as sp, shlex
sp.Popen(['echo 1']) # FAILS with "No such file or directory"
sp.Popen(['echo', '1']) # SUCCEEDS
sp.Popen(['echo 1'], shell=True) # SUCCEEDS, but extra overhead
sp.Popen(shlex.split('echo 1')) # SUCCEEDS, equivalent to #2

Without shell=True, Popen expects the executable to be the first element of args, which is why it fails, there is no "echo 1" executable. Adding shell=True invokes your system shell and passes the first element of args to the shell. i.e. for linux, Popen(['echo 1'], shell=True) is equivalent to Popen('/bin/sh', '-c', 'echo 1') which is more overhead than you may need. See Popen() documentation for cases when shell=True is actually useful.

回答3:

You have to give the full path to your program deactivate and then it the subprocess module should be able to find it.

回答4:

I'm spawning subprocesses like that:

SHUTDOWN_CMD = os.path.sep.join(["c:", "windows", "system32", "shutdown.exe"])

def abortShutdown():
    os.spawnv(os.P_NOWAIT, SHUTDOWN_CMD,
        [SHUTDOWN_CMD, '/A'])
    time.sleep(3)

I'm not using subprocess since Python 2.5 does not support it. I had to use use the FULL path to have it working and I guess you also have to use the full path to your custom commands.