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Spawn subshell for SSH and continue with program flow

Tags:

bash

ssh

I'm trying to write a shell script that automates certain startup tasks based on my location (home/campusA/campusB). I go to University and take classes in two different campuses (hence campusA/campusB). My location is determined by which wireless network I'm connected to. For the purposes of this script, we can assume that I will be connected to one of these networks when the script is called and my script knows which one I'm connected to based on a call to iwconfig.

This is what I want it to do:

cat file1 > file2 # always do this, regardless of where I am
if Im at home:
    start tweetdeck, thunderbird, skype

else if Im at campusA:
    activate the login script # I need to login on a webform before I get internet access. 
                              # I have written a script to automate this. 
                              # Wait for this script to finish before doing anything else
    myProg2 & # I want myProg2 running in the background until I shutdown my computer.

else if Im at campusB:
    ssh username@domain # this is the problematic line
    myProg2 & # I want myProg2 running in the background until I shutdown my computer.

start tweetdeck, thunderbird
close the terminal with the "exit" command

The problem is that campusB's wireless network is behind a firewall, which grants me internet access ONLY after I successfully ssh by username@domain. After a successful ssh, I need to keep the terminal window active in order to hold keep the internet access. If I close the terminal window, I lose internet access (this is bad).

When I try doing just ssh username@domain, the script stops because I don't exit the ssh command. I can't ^C out of it, which means that the rest of the script is never executed. I also have the same problem if I just close the terminal window in an attempt to kill the ssh session.

Some googling brought me to subshell, which I'm either using wrong or can't use to solve my problem. So how should I go about solving this problem? I'd appreciate any help - I've been at this for a while now and am unable to find anything helpful. If it makes a difference, I'd rather not store my ssh password in the script

Further, ampersanding the ssh call (ssh username@domain &) doesn't seem to do any good (can anyone explain why?)

Thank you in advance

EDIT

I must clarify, that the ssh connection has to be active in order for me to have internet access. Thus, when I close the terminal window, I need the ssh connection to still be active.

like image 272
inspectorG4dget Avatar asked Mar 03 '11 19:03

inspectorG4dget


1 Answers

I had a script that looped on 6 servers, calling via ssh in the background. In 1 part of the script, there was a mis-behaving vendor application; the application didn't 'let go' of the connection properly. (other parts of the script using ssh in background worked fine).

I found that using ssh -t -t cured the problem. Maybe this can help you too. (a teammate found this on the web, and we had spent so much time, I never went back to read the article that suggested this. The man page on our system gave no hint that such a thing was possible)

Hope this helps.

like image 69
shellter Avatar answered Oct 11 '22 20:10

shellter