Question

I'm including simple Expect commands within a bash script (I know I could be just writing a pure Expect script but I would like to get it to work from within bash).

The script is below:

#!/bin/bash

OUTPUT=$(expect -c '
spawn ssh mihail911@blah.org
expect "password:"
send "dog\r"
')

Upon ssh'ing to the above address, it will return something of the form mihail911's password: on the prompt so I think my expect line is valid. When I run this my script does not print anything. It does not even show the password: prompt. In general, even if I manually provide an incorrect password, I will receive a Incorrect password-type response prompt. Why is nothing printing and how can I get my script to execute properly? I have tried debugging by using the -d flag and it seems to show that at least the first expect prompt is being matched properly.

In addition, what values should I expect in the OUTPUT variable? When I echo this variable, it simply prints the first the first command of the expect portion of the script and then mihail911's password:. Is this what it's supposed to be printing?

Answer 1

#!/bin/bash
OUTPUT=$(expect -c '
        # To suppress any other form of output generated by spawned process
        log_user 0
        spawn ssh dinesh@xxx.xxx.xx.xxx
        # To match some common prompts. Update it as per your needs.
        # To match literal dollar, it is escaped with backslash
        set prompt "#|>|\\$"
        expect {
                eof     {puts "Connection rejected by the host"; exit 0}
                timeout {puts "Unable to access the host"; exit 0;}
                "password:"
        }
        send "root\r"
        expect {
                timeout {puts "Unable to access the host"; exit 0;}
                -re $prompt
        }
        send "date\r"
        # Matching only the date cmd output alone
        expect {
                timeout { puts "Unable to access the host";exit 0}
                -re "\n(\[^\r]*)\r"
        }
        send_user "$expect_out(1,string)\n"
        exit 1
')
echo "Expect's return value : $?"; # Printing value returned from 'Expect'
echo "Expect Output : $OUTPUT"

输出

dinesh@MyPC:~/stackoverflow$ ./Meric 
Expect's return value : 1
Expect Output : Wed Sep  2 09:35:14 IST 2015
dinesh@MyPC:~/stackoverflow$

Expect Script Return Value

1 个答案: