How to Deal with Junk Values in Remote SSH CLI Output with Paramiko?

Dealing with Junk Values in Remote SSH CLI Output via Paramiko

While using Python's Paramiko library for SSH connections and output retrieval from a remote machine's CLI, users may encounter unwanted junk values interspersed with the desired output. These values, often in the form of ANSI escape codes like "x1b[2Jx1b[1;1H", can clutter the output and hinder its usability.

Understanding the Source of Junk Values

Contrary to the assumption that they are junk, these escape codes are vital for proper output display in a terminal environment. They provide instructions to the terminal on how to format the text, move the cursor, and so on. However, if you are not using an interactive terminal, these codes can be problematic.

Solution: Executing Commands Interactively

By default, Paramiko's SSHClient.invoke_shell method initiates an interactive terminal session, which leads to the inclusion of escape codes. To eliminate this, switch to the exec_command method, which runs commands without a pseudo terminal (unless explicitly enabled):

<code class="python">stdin, stdout, stderr = client.exec_command('ls')</code>

Alternative Solutions

If for some reason you need to use the "shell" channel, you can manually create it without a pseudo terminal. Additionally, you can use the following workaround to remove the escape sequences from the string output:

<code class="python">import re
output = re.sub(r'(\x1b\[.*?m)', '', output)</code>

Decode Output Encoding

Note that the "u" character preceding the string output in the question denotes Unicode encoding. This is necessary for handling non-ASCII characters in the output.

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