Repeat a command on SSH server forever, via Plink or a python script

Question

Perhaps a python script would work for this simple automation. I need to connect via ssh to my router and run a command over and over. I understand that if I use Plink with a script I will probably have to repeat my command thousands of times. That would work but isn't there a better to just simply repeat the command?

For example, if i have to make a script my file would look like this:

/user/print
/user/print
/user/print
/user/print
/user/print
/user/print
/user/print
.....

You want something like `while true; do date; sleep 1; done` (replacing `date` with a command of your choice). — match, Feb 20 '18 at 21:32
I tried making a cmd.txt with the following: while true; do /user/print; sleep 1; done. Then I start putty like this: C:\Program Files\PuTTY>putty.exe -t -m cmd.txt -load "mysesseion" -l root -pw mypsss. It starts the session, then gives me a syntax error. — Mariyah, Feb 21 '18 at 04:34
Yes, it is a Mikrotik router. it has an SSH console. If I make a cmd.txt with a hundred lines of:` /user print` it works, but stops after a hundred, I just need to make it infinite and a 5 second pause in between — Mariyah, Feb 21 '18 at 13:45

Martin Prikryl · Accepted Answer · 2018-02-21T19:35:51.177

To do the loop on the server-side do:
```
plink username@example.com "while true; /user/print; done"
```
This has an advantage that you connect only once to the server.

To do the loop on the client-side do:
```
:loop
plink username@example.com /user/print
goto loop
```
See also How to create an infinite loop in Windows batch file?

If you can do Python, just loop the ssh.exec_command call.

import paramiko
import time

ssh = paramiko.SSHClient()
ssh.connect("example.com", username="username", password="password")

while True:
    print "Running"
    stdin, stdout, stderr = ssh.exec_command("/log print")
    print stdout.read()
    print stderr.read()
    print "Waiting"
    time.sleep(5)

The above is combined code from:

score 0 · Answer 2 · answered Nov 16 '18 at 19:53

You can use the vassal package, which is exactly designed for this.

All you need is to install vassal and do

from vassal.terminal import Terminal
from vassal.scheduler import Scheduler
shell = Terminal(["ssh username@host", "cd scripts", "python foo1.py", "python foo2.py"])
shell = Scheduler(shell, sec=1)
shell.run()

This will run the command once every second, and you can make it run faster to change sec=0.1.

Repeat a command on SSH server forever, via Plink or a python script

2 Answers2