UNIX for Dummies Questions & Answers

So, I have an expect script (let's call it expect.exp) that takes 3 arguments. It logs into a remote server, runs a set of commands, then hands control over to the user by the "interact" command. If I call this script from the command line, it works properly.

Now I'd like to apply this script to several servers-- log in, view the automated command output, interact as needed, log out, and get jumped straight to the next server. The reasonable approach, it seems, is to create a file that has the parameters in some nice format, like CSV, then use a wrapper to call the nice, proven expect script... something like:

Code:

while read LINE; do
     (assign each field of the line to a variable; say opt1, opt2, opt3)
     ./expect.exp opt1 opt2 opt3
done

I would expect this to log on, run the automated commands, hand me control, and wait for me to log off; then, once I've logged off that particular server, it would automatically log me onto the next one, run the automated commands, hand over control... you get the idea... until the list is finished. Instead, it logs on to the first server, runs the commands, apparently logs off, and drops me back to a prompt on the server I'm running this from. Only the first line of inputs is used. Why is that? This seems straightforward enough, but apparently it isn't. I'd like to understand this behavior and see how to fix it.

I am not sure if you code example was complete. I tried replicating with a simple shell script:

Code:

#!/bin/bash
echo $1 $2 $3

Then did the following:

Code:

while true; 
   do
      test.sh
   done

In this case, it doesn't process the arguments. If I do the following, which matches your example

Code:

while true; 
   do
      test.sh 1 2 3
   done

Then, no matter what I type, I will get 1 2 3 as output. Are you trying to be prompted for your opt1, opt2, opt3 arguments everytime? If so, this isn't the correct way to do it.

I would keep an iterator of the the number of hosts or times you wish to run your script, and move the readline way from the "while" line & change your expect script to prompt for the variables.

Ok, I've reviewed this a little more... when I rewrote my structure as a for loop instead of while, it worked. So, I suspect that the problem is in the while structure rather than the expect/bash interaction. Let me back-burner this and study it a bit more. Thanks for the reply, but it appears I might have given faulty information in my OP.