Automate Linux Server Tasks with Python: A Quick‑Start Guide to Paramiko

Overview

Paramiko is a Python library implementing the SSHv2 protocol, built on the cryptography package. It provides two main high‑level classes: SSHClient for executing remote commands and SFTPClient for file transfer.

Using SSHClient

Install with pip install paramiko. Typical workflow:

Create an SSHClient instance.

Set a policy for unknown host keys (e.g., AutoAddPolicy).

Connect to the remote host with connect(), supplying hostname, port, username, password or key.

Execute a command with exec_command() and read stdout / stderr.

Close the client.

# -*- coding: utf-8 -*-
import paramiko

client = paramiko.SSHClient()
client.set_missing_host_key_policy(paramiko.AutoAddPolicy())
client.connect(hostname='192.168.23.134', port=22,
               username='ftoz', password='123456')

stdin, stdout, stderr = client.exec_command('ls')
print(stdout.read().decode('utf-8'))

client.close()

connect() parameters: hostname – target address. port – default 22. username, password – password authentication. pkey or key_filename – private‑key authentication. timeout – optional TCP timeout. allow_agent, look_for_keys – enable SSH agent or key lookup in ~/.ssh. compress – enable compression.

set_missing_host_key_policy() options: AutoAddPolicy – automatically add unknown host keys to the local HostKeys object. WarningPolicy – issue a Python warning but accept the key. RejectPolicy – reject unknown keys (default).

Using SFTPClient

For file operations, obtain a Transport object, authenticate, then create an SFTPClient from it.

import paramiko

t = paramiko.Transport(('192.168.23.134', 22))
t.connect(username='ftoz', password='123456')
sftp = paramiko.SFTPClient.from_transport(t)

# Upload a local file
sftp.put('F:/S12312.txt', '/home/ftoz/zxc12312.txt')

# Download the same file
sftp.get('/home/ftoz/zxc12312.txt', 'F:/S12312.txt')

t.close()

Common SFTPClient methods: put(localpath, remotepath, callback=None, confirm=True) – upload a file; confirm triggers a stat() check. get(remotepath, localpath, callback=None) – download a file. mkdir(path, mode=511) – create a directory. remove(path) – delete a file. rename(oldpath, newpath) – rename a file or directory. stat(path) – retrieve file attributes. listdir(path='.') – list directory contents.

Always close the SSHClient or Transport after operations to release resources.