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The only simple way to do SSH in Python today is to use subprocess + OpenSSH...
#!/usr/bin/python
# All SSH libraries for Python are junk (2011-10-13).
# Too low-level (libssh2), too buggy (paramiko), too complicated
# (both), too poor in features (no use of the agent, for instance)
# Here is the right solution today:
import subprocess
import sys
HOST="www.example.org"
# Ports are handled in ~/.ssh/config since we use OpenSSH
COMMAND="uname -a"
ssh = subprocess.Popen(["ssh", "%s" % HOST, COMMAND],
shell=False,
stdout=subprocess.PIPE,
stderr=subprocess.PIPE)
result = ssh.stdout.readlines()
if result == []:
error = ssh.stderr.readlines()
print >>sys.stderr, "ERROR: %s" % error
else:
print result
@bortzmeyer
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Author

ssh = subprocess.Popen(["ssh", "%s" % HOST, "%s" %COMMAND],
shell=True,
stdout=subprocess.PIPE,
stderr=subprocess.PIPE)

You should read the documentation. https://docs.python.org/3/library/subprocess.html Executive summary: shell=True is both dangerous and a bad idea in most cases. From a Python program, shell=False is the right solution most of the time. (See in the doc, around "If shell is True, it is recommended to pass args as a string rather than as a sequence.")

@datlife
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datlife commented Nov 4, 2019

SSH without third-party library

Here is my take on SSH without using third-party library. I leveraged a concept of fork system call in UNIX [1].

# Create an ssh session with python
import os
import shlex

def create_ssh(host, user):
  """Create a ssh session"""
  ssh = "/usr/bin/ssh -t {user}@{host} ".format(user=user, host=host)
 
  # Now, fork a child from current process 
  # This is a basic concept from Operating System class.
  pid = os.fork()
  if pid == 0:  # a child process
     print("Executing: %s" %(ssh))
     cmd = shlex.split(ssh)
     os.execv(cmd[0], cmd)
  
  os.wait(pid, 0)
  print("ssh session is finished. :)")
 
if __name__ == "__main__":
  create_ssh(
      host="remote_host", 
      user="remote_user")

Ref:
[1] https://en.wikipedia.org/wiki/Fork_(system_call)

@Insektosaurus
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Insektosaurus commented Jan 11, 2020

Amazing

Still populating top three google results when searching for 'python3 connect ssh and run script' :)

@faddison
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faddison commented May 6, 2020

Still true today. Amazing how badly libraries like paramiko and fabric fail at such a simple task.

@rogercallster
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Still a valid chain but still finding it hard to reliably send password from Osx or linux

@hoon0912
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hoon0912 commented Jan 7, 2021

thank you

@HungPhann
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Can tell how amazing it is when this solution still works today.
Thanks a lot.

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