How to Eliminate Junk Output When Retrieving CLI Output with Paramiko?

Can You Eliminate Junk Output When Using SSH to Retrieve CLI Output with Python's Paramiko?

When utilizing Python's Paramiko library to SSH into a remote device and retrieve output from the command-line, it is common to encounter extraneous characters alongside the intended output. This can include ANSI escape codes and other non-essential information.

While these characters may seem like junk, they actually serve a purpose. ANSI escape codes are used by terminal clients to enhance the presentation of output, such as text formatting and cursor positioning. They are not, therefore, a nuisance but rather a necessary component of interactive terminal sessions.

When using Paramiko's SSHClient.invoke_shell method, which is intended for interactive terminal sessions, the library automatically requests a pseudo terminal. This terminal is used to interpret the ANSI escape codes and display the output in a human-readable format.

However, if your intention is to automate the execution of remote commands rather than engage in interactive terminal sessions, the appropriate method to use is SSHClient.exec_command. This method does not allocate a pseudo terminal by default, thereby eliminating the issue of extraneous characters.

Alternatively, if you require the use of the "shell" channel due to specific server constraints, you can manually create the channel without the pseudo terminal. However, it is important to note that Paramiko's SSHClient.invoke_shell does not support this functionality, so you will need to create the channel yourself.

Lastly, the "u" prefix that you may notice in the output is not part of the string value itself. Rather, it indicates that the string is encoded in Unicode, which is essential for handling characters that fall outside the ASCII range.

The above is the detailed content of How to Eliminate Junk Output When Retrieving CLI Output with Paramiko?. For more information, please follow other related articles on the PHP Chinese website!