Run cat on remote computer and send output a variable using expect

Question

I have a bash+expect script which has to connect via ssh to the remote comp (and i can't use ssh keys, need password identification in here), read the file there, find specific line with the "hostname" (like "hostname aaaa1111") and store this hostname into the variable to be used after while. How can i get the value of the "hostname" parameter? I thought that line content will be in $expect_out(buffer) variable (so i can scan it and analyze), but it's not. My script is:

    #!/bin/bash        
    ----bash part----
    /usr/bin/expect << ENDOFEXPECT
    spawn bash -c "ssh root@$IP"  
    expect "password:"
    send "xxxx\r"
    expect ":~#"
    send "cat /etc/rc.d/rc.local |grep hostname \r"
    expect ":~#"
    set line $expect_out(buffer)
    puts "line = $line, expect_out(buffer) = $expect_out(buffer)"
    ...more script...
    ENDOFEXPECT

When i try to see line variable, i see only this: line = , expect_out(buffer) = (buffer) What is the right way to get the line from the file into the variable? Or is it possible to open the file on the remote computer with expect, scan the file and get what i need to the variable? Here http://en.wikipedia.org/wiki/Expect there is an example:

    # Send the prebuilt command, and then wait for another shell prompt.
    send "$my_command\r"
    expect "%"
    # Capture the results of the command into a variable. This can be displayed, 
    set results $expect_out(buffer)

seems that it doesn't work in this case?

Answer 1

You might just want to try and do it all from expect, as expect can control bash.

The following should do what you've described. Not sure if this is exactly what you are trying to do.

#!/bin/sh
# the next line restarts using tclsh \
exec expect "$0" "$@"


spawn bash 
send "ssh root@$IP\r"
expect "password:"
send "xxxx\r"
expect ":~#"
send "cat /etc/rc.d/rc.local |grep hostname \n"
expect ":~#"
set extractedOutput $expect_out(buffer)
set list [split $extractedOutput "\n"]
foreach line $list {
    set re {(?x)
        .*
        (*)              
        -S.*
    }
    regexp $re $line total extractedValue
    if {[info exists extractedValue] && [string length $extractedValue] > 1} {
        set exportValue $extractedValue
        break    # We've got a match!
}

send "exit\r" # disconnect from the ssh session

if {[info exists exportValue] && [string length $exportValue] > 1}{
    send "export VARIABLE $exportValue\r"
} else {
    send_user "No exportValue was found - exiting\n"
    send "exit\r"
    close
    exit 1
}

# now you can do more things in bash if you like