CODEWITHSUNDEEP
bashtclexpect
tlre0952b
tlre0952b

Reputation: 751

Send <command>, expect with conditional testing?

I have an expect script wrapped in a bash script for doing specific commands depending on whether an IP address is pulled from the Cisco router. The algorithm that I'm trying to code is something like the following:

send -h "ip int br"
expect -re {
    if "192\.[0-9]{1,3}\.{2}[0-9]{1,3}"
    {
        expect 
        {
            "up/up { do these things here }
            "down/down" { do this instead }
        }
    }
    else
    {
        send -h "<another command>"
        expect
        {
            "up/up" { do this }
            "down/down" { or this if down }
        }
    }
}

How can I do this? I have tried using expect's equivalent of the switch statements with the -ex flag as suggested in an answer to another user's question (Making decisions on expect return) but haven't had any result with that.

Any ideas?

Upvotes: 0

Views: 243

Answers (1)

glenn jackman
glenn jackman

Reputation: 247230

I would capture the returned address and then act on it. I see repeated code, so try to reduce that:

send -h "ip int br"
expect {
    timeout {error "can't find an ip address after 'ip int br' command"}
    -re {\m\d{1,3}(\.\d{1,3}){3}\M}
}
if { ! [regexp {192\.[0-9]{1,3}\.{2}[0-9]{1,3}} $expect_out(0,string)]} {
    send -h "<another command>"
}
expect {
    "up/up" { do these things here }
    "down/down" { do this instead }
}

Other notes:

  • Take care in expect to put the opening brace of a block NOT on it's own line, but cuddled with the command.
  • Put regular expressions in {braces} because this "192\.[0-9]{1,3}\.{2}[0-9]{1,3}" will give you an error like invalid command name "0-9" -- brackets are special to Tcl and need to be escaped unless they're in braces.

Upvotes: 1

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