Cisco Configuration “Expect” Backup Script

I was recently tasked with backing up switch configurations automatically. No problem, right? Wrong. There was nothing to spend on this project so it was up to me and whatever I could do with a script. I had made a telnet script in the past but was not crazy about passwords flying around in plain text. I really have very little scripting experience so many of you will find this very easy to understand and follow since there is nothing complicated about my scripting skills.

I used a Linux based system and the “expect” scripting language. Expect is great for automating tasks that are typically interactive. I could have used PERL or PHP (I am a bit more familiar with them) but apparently their SSH libraries don’t always play well with Cisco SSH servers. At any rate the expect script was easy enough and I set it up to take arguments that would be fairly interfaceable anyhow. The only pre requisite is to install “expect” on your system. Check the script out below:

set timeout 15
set host [lindex $argv 0]
set username [lindex $argv 1]
set password [lindex $argv 2]
set tftp [lindex $argv 3]
set file [lindex $argv 4]
#Open the SSH session
spawn ssh -l $username $host
sleep 2
#Catch the password prompt and send supplied password
expect {
"word:" {send "$password\r"}
sleep 1
#Catch the enabled prompt and issue the command to backup configuration
expect {
"#" {send "copy startup-config tftp:\r"}
sleep 1
#Expect the two confirmation questions and answer
expect {
"?" {send "$tftp\r"}
sleep 1
expect {
"?" {send "$file\r"}
#Wait long enough for file transfer and exit
sleep 10

To use the script simpley follow this convention:

# ./script.exp  device username password tftp_server backup_filename

If you would like to learn more about Expect I suggest the book “Exploring Expect”
to get you familiar with the basics as well as some advanced Expect features.

I hope someone else finds this adaptable to their needs! As always, feel free to comment, and post changes or enhancements!

Download Script HERE

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