hello-pyworld

# run method 用于執行一個命令并返回命令的output.
# 注意， 返回值是byte 格式
# pexpect 是類似手動操作， run method 的上下文就是當前child process 環境。
# example
import pexpect


cmd = "ssh username@localhost"
child = pexpect.spawn(cmd)
index = child.expect(".*password:")
if index == 0:
    child.sendline("password") # send password
    index = child.expect("DESKTOP-5C:") # 等待提示符
    if index == 0:
        print("congratulations") # login 成功
        rst = pexpect.run("ifconfig")
        print(f"rst  is  {rst}")

- spawn method 用于開啟一個子進程， 并返回子進程
- expect method 用于等待子進程返回pattern 字符串。
import pexpect


# start a child process with spawn
# It just echos geeksforgeeks
child = pexpect.spawn("echo hai geeksforgeeks")


# prints he matched index of string.
print(child.expect(["hai", "welcome", "geeksforgeeks", "DESKTOP"])) #

-- 給child.logfile assign一個文件接口， 所有信息都會被保留， 包括交互的信息， 就跟手動操作是一樣的
-- 注意pexepct 的返回都是byte 格式， 所以file open format 一定要是"b" format
-- 此例子中有用到sendline 方法， send line 用法不言而明。 
import pexpect
import sys


logfilehandle = open("aa.log","ab")
cmd = "ssh username@localhost"
child = pexpect.spawn(cmd)
child.logfile = logfilehandle
index = child.expect(".*password:")
if index == 0:
    child.sendline("password") # send password
    index = child.expect("DESKTOP-5C:")
    if index == 0:
        print("congratulations")
        child.sendline("ifconfig")
        child.sendline("echo finished")
        index = child.expect("DESKTOP-5C3GASH:")
        if index == 0:
            print("child after:")
            rst = child.before
            rst_lines = rst.decode('gbk').split("\r\n")
            for i in rst_lines:
                print(f"---{i}")
logfilehandle.close()