Python子进程stdout.readlines（）被卡住

Question

I am trying to use to python subprocess module in order to ssh to a server and then switch to a super user and then ls and print the folders in the terminal.

My Code:

def sudo_Test():
    HOST = 'Host'
    PORT = '227'
    USER = 'user'
    cmd='sudo su - ec2-user;ls'

    process = subprocess.Popen(['ssh','-tt','{}@{}'.format(USER, HOST),
                            '-p',PORT,cmd],
                           shell=False,
                           stdout=subprocess.PIPE,
                           stderr=subprocess.PIPE,
                           stdin=subprocess.PIPE)
    process.stdin.write("my_password\r\n")

    print "stuck here VVV"
    result = process.stdout.readlines()
    print "finished it"

    if not result:
        print "Im an error"
        err = process.stderr.readlines()
        print('ERROR: {}'.format(err))
    else:
        print "I'm a success"
        print result

print sudo_Test()

Console output when I run this:

dredbounds-computer:folder dredbound$ python terminal_test.py
stuck here VVV

For some reason the code gets stuck on the line result = process.stdout.readlines(). I have to cntrl+c to exit out of the terminal session when this happens. It works fine if I just do cmd='sudo; ls' instead of cmd='sudo su - ec2-user;ls'.Anyone know what I'm doing wrong or how I can get this to work?

Update: I changed cmd='sudo su - ec2-user;ls' -> cmd='sudo su - ec2-user ls' in the code above. Now I am getting the following error:

['password\r\n', '\r\n', '/bin/ls: /bin/ls: cannot execute binary   file\r\n']

I'm not sure why it thinks ls is a binary file now, but is there anyway i can tell it that it is just a terminal command so it returns a list of directories?

Answer 1

The problem is here:

sudo su - ec2-user;ls

sudo su - ec2-user opens a shell and waits for input. You need to send the shell an exit command (or close its stdin) before the shell exits and the ls command is run.

If your goal was to run ls as user ec2-user , then try:

sudo -u ec2-user ls

In other words, replace

cmd='sudo su - ec2-user;ls'

With:

cmd='sudo -u ec2-user ls'