Command executed with Paramiko does not produce any output

Question

When I try to do

stdin, stdout, stderr = client1.exec_command('glass-version')
print stdout.readlines()

I am getting an empty output.

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An expected output is:

===================== GLASS version details =====================
 GLASS version : 1.2.3
=================================================================

Answer 1

If you get no output on stdout, it is usually because the command fails to start.

Read stderr to check for any errors.

print(stderr.readlines())

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Quite often the error is "<command> not found". For that see
Some Unix commands fail with "<command> not found", when executed using Python Paramiko exec_command

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If you are connecting to a device, see also Executing command using Paramiko exec_command on device is not working.