How to Fix Improperly Formatted Output When Using SSH with Python pexpect

Опубликовано: 07 Апрель 2025
на канале: vlogize

Learn how to resolve formatting issues when retrieving output from a remote server using SSH with Python. This guide provides clear solutions for proper output display.
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This video is based on the question https://stackoverflow.com/q/72897629/ asked by the user 'ivbtar' ( https://stackoverflow.com/u/7095217/ ) and on the answer https://stackoverflow.com/a/72898417/ provided by the user 'pynexj' ( https://stackoverflow.com/u/900078/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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How to Fix Improperly Formatted Output When Using SSH with Python pexpect

When executing Python scripts to interact with remote servers over SSH, many users encounter an issue with their output being improperly formatted. Specifically, the output displays with unwanted \r\n characters, making it difficult to read. This guide will explore this problem and guide you through practical solutions to achieve a clean and properly formatted output.

The Problem: Unexpected Formatting of Output

Imagine you're connecting to a remote server to retrieve a Python script using the pexpect library. You run the following code:

[[See Video to Reveal this Text or Code Snippet]]

However, the output you receive looks something like this:

[[See Video to Reveal this Text or Code Snippet]]

This shows the script content poorly formatted, making it hard to read. You'd prefer it to output as follows:

[[See Video to Reveal this Text or Code Snippet]]

The struggle is real! Fortunately, the solution is straightforward.

The Solution: Decoding Output Correctly

Understanding the Issue

The reason behind the unexpected \r\n formatting lies in the fact that the data captured in s.before is received in bytes format rather than the more readable str format. To format the output correctly, it needs to be decoded.

Steps to Fix the Formatting

To solve the problem, you have a couple of options:

Decode the Bytes using UTF-8:

Modify your existing print statement to decode the bytes directly before printing:

[[See Video to Reveal this Text or Code Snippet]]

By adding .decode(), the bytes will be converted to a proper string, removing the \r\n issues.

Set Encoding in pxssh:

Alternatively, if you prefer to automatically handle encoding in your connection setup, you can specify the encoding directly when initializing pxssh:

[[See Video to Reveal this Text or Code Snippet]]

This way, pexpect will handle character encoding for you, providing cleaner output without having to decode it manually every time.

Final Code Example

Here’s how your updated code may look using the first solution:

[[See Video to Reveal this Text or Code Snippet]]

Conclusion

By implementing these relatively simple changes, you can ensure that your output is clean and formatted correctly, making it easy to read and understand. Whether you choose to decode the bytes manually or set encoding in pxssh, you'll notice a significant improvement in your output when connecting to remote servers.

Feel free to reach out if you have any questions or need further assistance with your Python scripting!