Bash – expect: how to use expect scripts from within a bash subroutine

bashexpect

I want to write a login script in expect. But I want this to be reused in different other scripts. I want to make all the login commands part of a bash subroutine. ie instead of

expect_login.sh
#!/bin/usr/expect -f
spawn ....
set ....

I want this:

expect_login
{
    # put some necessary command to initiate expect program

    spawn ...
    set ...
}

so I would like to place this subroutine in one file/library that would be reused by many different scripts.

How can I do that?

Thanks

PS: Pardon my imprecise syntax of bash/expect. I just wanted to write in a pseudocode manner.

Best Answer

I would go for 2 part solution. One part is the expect script, the other part is the Shell script.

For the expect script, it should be a generic script that accept input, and produce output.

This is my example expect script that accept hostname and password, and will produce the vcprofile name for the server

[user@server ~]$ cat getvcprofile.expect
#!/usr/bin/expect

set timeout 2

set host [lindex $argv 0]

set password [lindex $argv 1]

spawn ssh "ADMIN\@$host"

expect_after eof { exit 0 }

expect  "yes/no" { send "yes\r" }

expect  "assword" { send "$password\r" }

expect "oa>" { send "show vcmode\r" }

expect "oa>" { send "exit\r" }

exit

In the shell script, I will call the expect script and providing it with the variable, in this case the hostname for vcsystem. The password is actually a pattern according to the hostname OA@XXXX - where the XXXX is the last 4 digit number of the server

[user@server ~]$ cat getvcprofile.sh
#/bin/bash

# get VC profile for a host

host=$1

#get the blade enclosure
enclosure=`callsub -enc $host |grep Enclosure: | cut -d" " -f2`

if [ ! -z $enclosure ]; then

#get the last 4 digit of the enclosure
fourdigit=${enclosure: -4}

domain=`./getvcprofile.expect ${enclosure}oa OA@${fourdigit} |grep Domain|awk '{print $NF}'`
echo $domain

else

echo "None"

fi

With this 2 part solution, I can do something like this:

for X in `cat serverlist.txt`; do echo -n $X": "; ./getvcprofile.sh $X; done

And it will print out the vcprofile for each of the servers in the file serverlist.txt

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