How to capture the output of executed command (python paramiko )?

Question

I am executing certain commands and would like to capture the output of the same.

import paramiko

ssh = paramiko.SSHClient()
ssh.set_missing_host_key_policy(paramiko.AutoAddPolicy())
ssh.connect(ip,username="username",password="pwd")
stdin, stdout, stderr = ssh.exec_command("whoami")
out = stdout.read()
print out           # prints username
print stdout.read() # prints nothing, why is it so ?
                    # Instance #1

stdin, stdout, stderr = ssh.exec_command("kill -9 1111")
out = stdout.read()
print out #prints nothing. expected as it doesn't capture if it's successful
# print out # should print "-bash: kill: (1111) - No such process" , if it doesn't exist 
#--> Instance #2

In Instance #1, why print stdout.read() , prints nothing ?

In Instance #2, How to capture such outputs/response ?

pynexj · Accepted Answer · 2017-08-20 15:13:22Z

2

instance #1

out = stdout.read()
print stdout.read()

The first stdout.read() has already consumed all the output so the second stdout.read() returns nothing.

instance #2

Usually error messages would print to stderr so you should use stderr.read() to get the error.

answered Aug 20, 2017 at 15:13

pynexj

21.3k6 gold badges45 silver badges63 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

jino dav · Accepted Answer · 2017-11-24 11:11:48Z

0

It probably prints nothing because stdout is empty because of an error in the execution. Try printing stderr instead of stdout

answered Nov 24, 2017 at 11:11

jino dav

612 silver badges5 bronze badges

Collectives™ on Stack Overflow

How to capture the output of executed command (python paramiko )?

2 Answers 2

instance #1

instance #2

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

instance #1

instance #2

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related