Automatically enter username and password during Python terminal program execution

Automatically Enter Username and Password During Python Terminal Program Execution

In actual development, you may need to write Python terminal programs to automate tasks. Some of these tasks require users to enter sensitive information such as usernames and passwords. For security reasons, you can write programs to automatically enter usernames and passwords during execution, eliminating the need for users to manually enter this information.

In this article, we will describe how to use Python to write a terminal program that automatically enters usernames and passwords during execution.

Preparation

Before we begin writing our program, we need to install a Python module called pexpect. pexpect is a Python module for controlling interactive programs. It allows you to simulate user input, control, and monitor other programs in Python.

You can install the pexpect module using the following command:

pip install pexpect

Writing Python Programs

The following is a simple Python program that simulates automatically entering a username and password during terminal program execution:

import pexpect

def auto_input(username, password):
command = "your_command" # Terminal command to be executed

child = pexpect.spawn(command)

child.expect("Username:")
child.sendline(username)

child.expect("Password:")
child.sendline(password)

child.expect(pexpect.EOF)

if __name__ == "__main__":
username = "your_username"
password = "your_password"

auto_input(username, password)

In the above code, pexpect.spawn(command) is used to execute the terminal command, child.expect("Username:") is used to wait for the terminal program to output a prompt message, and child.sendline(username) is used to send the username. Next, the program waits for the terminal program to output a password prompt message using child.expect("Password:") and sends the password using child.sendline(password). Finally, child.expect(pexpect.EOF) indicates that it has waited for the program to terminate.

Running Example

Suppose we have a simple terminal program example_program.sh with the following content:

#!/bin/bash

echo "Welcome to Example Program"
read -p "Username: " username
read -sp "Password: " password
echo
echo "Login successful"

We can use the above Python program to simulate automatically entering the username and password during the execution of example_program.sh. Assuming our username is example_user and our password is example_password, we can modify your_command, your_username, and your_password in the Python program above to ./example_program.sh, example_user, and example_password.

Then run the Python program, and you’ll see the following output in the terminal:

Welcome to Example Program
Username: example_user
Password: Login successful

As can be seen from the output above, we successfully simulated the automatic entry of the username and password during execution, achieving our goal.

Summary

Through this article, we learned how to use the Python pexpect module to automatically input usernames and passwords during terminal program execution. This approach is very useful when writing automated tasks that require simulated user input, improving efficiency and reducing user interaction.