我正在使用paramiko软件包为服务器创建SSH。
我编写了以下代码（模块的一部分），该代码应执行一些命令并返回其输出。
def exec_and_get_remote_output(self, cmd, decode=True, splitlines=True, ssh_close=False):
"""
Execute remote command and return output
:param cmd: command to execute (string)
:param decode: perform decoding from binary (bool)
:param splitlines: perform splitting to get list of lines (bool)
:param ssh_close: close SSH session after execution (bool)
:return: command output as sting or list of lines
"""
if CHECK_NONE(self._client):
logger.debug('ssh client is None')
return None
if not self._opened:
self.open_connection()
chan = self._client.get_transport().open_session()
chan.exec_command(cmd)
logger.debug('Executed SSH command: {}'.format(cmd))
raw_output = self.receive_output(chan)
if decode and splitlines:
output = self._decode_raw(raw_output)
elif decode and not splitlines:
output = self._decode_raw(raw_output, splitlines=False)
else:
output = raw_output
logger.debug('Raw output:\n{}'.format(output))
# Perform cleanup
self.cleanup(chan, ssh_close)
return output
此代码应执行一些命令（作为字符串传递），然后解析通道的输出。
当我使用简单的shell命令调用此方法时，会根据需要获取输出。
[例如：print(self.ssh.exec_and_get_remote_output("ls"))]
现在，当我尝试在该服务器外壳中运行一些CLI进程时，我的问题就会出现，该过程应该从外壳中获取输入（用户输入），然后将输出返回到外壳中（在屏幕上打印出来），在这种情况下为chan。 exec_command返回None (NoneType而不是[stdin,stdout,stderr]元组，并且raw_output变量（来自通道的输出）也返回为None，因此最终没有打印任何内容，我没有抛出任何异常SshException，因此我知道执行此命令是成功的。
这很奇怪，因为当我以交互方式执行此操作（手动连接到服务器）并运行连接到Shell的命令时，所有内容都会正常打印。在终端上。
[例如：print(self.ssh.get_remote_output("echo -e 'show cable rpd' | /opt/confd/bin/confd_cli --noaaa "))]
我阅读了exec_command用户手册，没有看到任何应引起这种行为的东西。
这是我从记录器获取的日志：
DEBUG:paramiko.transport:starting thread (client mode): 0x75a745c0
DEBUG:paramiko.transport:Local version/idstring: SSH-2.0-paramiko_2.4.2
DEBUG:paramiko.transport:Remote version/idstring: SSH-2.0-OpenSSH_7.4p1 Debian-10+deb9u6
INFO:paramiko.transport:Connected (version 2.0, client OpenSSH_7.4p1)
DEBUG:paramiko.transport:kex algos:['curve25519-sha256', 'curve25519-sha256@libssh.org', 'ecdh-sha2-nistp256', 'ecdh-sha2-nistp384', 'ecdh-sha2-nistp521', 'diffie-hellman-group-exchange-sha256', 'diffie-hellman-group16-sha512', 'diffie-hellman-group18-sha512', 'diffie-hellman-group14-sha256', 'diffie-hellman-group14-sha1'] server key:['ssh-rsa', 'rsa-sha2-512', 'rsa-sha2-256', 'ecdsa-sha2-nistp256', 'ssh-ed25519'] client encrypt:['chacha20-poly1305@openssh.com', 'aes128-ctr', 'aes192-ctr', 'aes256-ctr', 'aes128-gcm@openssh.com', 'aes256-gcm@openssh.com'] server encrypt:['chacha20-poly1305@openssh.com', 'aes128-ctr', 'aes192-ctr', 'aes256-ctr', 'aes128-gcm@openssh.com', 'aes256-gcm@openssh.com'] client mac:['umac-64-etm@openssh.com', 'umac-128-etm@openssh.com', 'hmac-sha2-256-etm@openssh.com', 'hmac-sha2-512-etm@openssh.com', 'hmac-sha1-etm@openssh.com', 'umac-64@openssh.com', 'umac-128@openssh.com', 'hmac-sha2-256', 'hmac-sha2-512', 'hmac-sha1'] server mac:['umac-64-etm@openssh.com', 'umac-128-etm@openssh.com', 'hmac-sha2-256-etm@openssh.com', 'hmac-sha2-512-etm@openssh.com', 'hmac-sha1-etm@openssh.com', 'umac-64@openssh.com', 'umac-128@openssh.com', 'hmac-sha2-256', 'hmac-sha2-512', 'hmac-sha1'] client compress:['none', 'zlib@openssh.com'] server compress:['none', 'zlib@openssh.com'] client lang:[''] server lang:[''] kex follows?False
DEBUG:paramiko.transport:Kex agreed: ecdh-sha2-nistp256
DEBUG:paramiko.transport:HostKey agreed: ssh-ed25519
DEBUG:paramiko.transport:Cipher agreed: aes128-ctr
DEBUG:paramiko.transport:MAC agreed: hmac-sha2-256
DEBUG:paramiko.transport:Compression agreed: none
DEBUG:paramiko.transport:kex engine KexNistp256 specified hash_algo <built-in function openssl_sha256>
DEBUG:paramiko.transport:Switch to new keys ...
DEBUG:paramiko.transport:Adding ssh-ed25519 host key for [10.40.2.142]:2022: b'c145a1e3b7fc4252387d5930a73cc2c9'
DEBUG:paramiko.transport:userauth is OK
INFO:paramiko.transport:Authentication (password) successful!
DEBUG:framework.ssh_client:SSH connection to 10.40.2.142:2022 is open
DEBUG:framework.ssh_client:This message should appear on the console:
DEBUG:paramiko.transport:[chan 0] Max packet in: 32768 bytes
DEBUG:paramiko.transport:Received global request "hostkeys-00@openssh.com"
DEBUG:paramiko.transport:Rejecting "hostkeys-00@openssh.com" global request from server.
DEBUG:paramiko.transport:[chan 0] Max packet out: 32768 bytes
DEBUG:paramiko.transport:Secsh channel 0 opened.
DEBUG:framework.ssh_client:Executed SSH command: /opt/confd/bin/confd_cli --noaaa
DEBUG:framework.ssh_client:Attempt #1 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #2 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #3 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #4 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #5 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #6 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #7 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #8 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #9 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #10 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #11 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #12 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #13 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #14 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #15 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #16 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #17 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #18 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #19 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #20 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #21 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #22 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #23 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #24 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #25 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #26 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #27 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #28 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #29 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #30 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #31 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #32 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #33 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #34 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #35 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #36 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #37 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #38 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #39 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #40 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #41 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #42 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #43 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #44 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #45 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #46 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #47 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #48 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #49 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #50 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #51 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #52 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #53 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #54 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #55 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #56 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #57 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #58 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #59 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #60 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #61 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #62 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #63 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #64 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #65 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #66 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #67 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #68 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #69 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #70 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #71 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #72 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #73 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #74 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #75 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #76 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #77 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #78 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #79 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #80 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #81 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #82 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #83 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #84 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #85 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #86 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #87 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #88 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #89 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #90 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #91 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #92 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #93 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #94 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #95 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #96 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #97 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #98 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #99 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Attempt #100 to check data in the channel:
DEBUG:framework.ssh_client:Data is NOT ready yet to be read from channel. Waiting 0.1 seconds
DEBUG:framework.ssh_client:Data is not ready to be read from channel. All 100 attempts are exhausted
DEBUG:framework.ssh_client:ERROR: Unable to get remote output
DEBUG:framework.ssh_client:Raw output:
None
DEBUG:paramiko.transport:[chan 0] EOF sent (0)
答案 0 :(得分：0)
paramiko中有两个不同的 exec_command函数。
您执行的那个不应该返回任何值。
使用paramiko.SSHClient.exec_command返回(stdin, stdout, stderr)。
以下详细信息：
http://docs.paramiko.org/en/2.4/api/channel.html?highlight=exec_command http://docs.paramiko.org/en/2.4/api/client.html?highlight=exec_command
文档字符串：
>>> help(paramiko.channel.Channel.exec_command)
Help on method exec_command in module paramiko.channel:
exec_command(self, *args, **kwds) unbound paramiko.channel.Channel method
Execute a command on the server. If the server allows it, the channel
will then be directly connected to the stdin, stdout, and stderr of
the command being executed.
When the command finishes executing, the channel will be closed and
can't be reused. You must open a new channel if you wish to execute
another command.
:param str command: a shell command to execute.
:raises:
`.SSHException` -- if the request was rejected or the channel was
closed
>>> help(paramiko.SSHClient.exec_command)
Help on function exec_command in module paramiko.client:
exec_command(self, command, bufsize=-1, timeout=None, get_pty=False, environment=None)
Execute a command on the SSH server. A new `.Channel` is opened and
the requested command is executed. The command's input and output
streams are returned as Python ``file``-like objects representing
stdin, stdout, and stderr.
:param str command: the command to execute
:param int bufsize:
interpreted the same way as by the built-in ``file()`` function in
Python
:param int timeout:
set command's channel timeout. See `.Channel.settimeout`
:param dict environment:
a dict of shell environment variables, to be merged into the
default environment that the remote command executes within.
.. warning::
Servers may silently reject some environment variables; see the
warning in `.Channel.set_environment_variable` for details.
:return:
the stdin, stdout, and stderr of the executing command, as a
3-tuple
:raises: `.SSHException` -- if the server fails to execute the command