TcL Scripting for Cisco IOS

Book excerpt: A guide to building and modifying Tcl scripts to automate network administration tasks Streamline Cisco network administration and save time with Tcl scripting Cisco networking professionals are under relentless pressure to accomplish more, faster, and with fewer resources. The best way to meet this challenge is to automate mundane or repetitive tasks wherever possible. In this book, three Cisco experts show you how to use Tcl scripting for Cisco IOS devices to do just that. You’ll learn easy techniques for creating, using, and modifying Tcl scripts that run directly on Cisco network devices from the Cisco IOS command line. The authors first teach basic Tcl commands and concepts for capturing and manipulating data and for querying or controlling Cisco equipment. Building on these core skills, they show you how to write scripts that automate and streamline many common IOS configuration, monitoring, and problem-solving tasks. The authors walk through the entire script development process, including planning and flowcharting what you want to accomplish, formatting your code, adding comments, and troubleshooting script errors. They also present many downloadable sample scripts, along with practical guidance for adapting them to your own environment. Whatever your role in managing, monitoring, or securing Cisco IOS networks and equipment, this book will help you get the job done more rapidly and efficiently. Automate routine administration tasks you’ve always performed manually Instantly collect and modify IOS router configurations and other data Write Syslog scripts to document failures, monitor network health, collect statistics, and send alarm messages Implement automated network performance measurement using IP SLA Use the Embedded Event Manager’s event detectors, server, and policies to customize device operation Trigger preplanned actions to correct problems as they arise Simplify policy management using the Tcl script refresh feature Protect Tcl script security with digital signatures and PKI Understand how Tcl functions within the Cisco IOS environment Master Tcl syntax and commands through hands-on practice Learn best scripting practices through expert examples Quickly modify this book’s examples for your own environment This book is part of the Networking Technology Series from Cisco Press®, which offers networking professionals valuable information for constructing efficient networks, understanding new technologies, and building successful careers.