Execute multiple dependent commands individually with Paramiko and find out when each command finishes

Question

I am writing a program in Python which must communicate through SSH with a physical target, and send to this targets some commands automatically (it is for testing).

Answer 1

It seems that you want to implement an interactive shell, yet you need to control individual commands execution. That's not really possible with just SSH interface. "shell" channel in SSH is black box with an input and output. So there's nothing in Paramiko that will help you implementing this.

If you need to find out when a specific command finishes or where an output of a specific command ends, you need to use features of a shell.

You can solve that by inserting a unique separator (string) in between and search for it in the channel output stream. With a common *nix shells something like this works:

channel = ssh.invoke_shell()
channel.send('cd /mytargetRep\n')
channel.send('echo unique-string-separating-output-of-the-commands\n')
channel.send('./executeWhatIWant\n')

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Though I do not really think that you need that very often. Most commands that are needed to make a specific commands working, like cd or set, do not really output anything.

So in most cases you can use SSHClient.exec_command and your code will be a way simpler and more reliable:
Execute multiple commands in Paramiko so that commands are affected by their predecessors

Even if you need to use something seemingly complex like su/sudo, it is still better to stick with SSHClient.exec_command:
Executing command using "su -l" in SSH using Python

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For a similar question (for "exec" channel), see:
How to get each dependent command execution output using Paramiko exec_command