In my last post I talked about how to enable and disable the Tool command Language (TCL) in a Cisco router or a Cisco Catalyst Switch, suppose if you want to use a ping command for more than 50 hosts,you don’t need to ping each and every single host from the Cisco router or a Cisco Catalyst Switch, in this scenario you can make use of TCL scripts, I will provide you a sample script to ping 10 hosts at a time from a Cisco Catalyst 6506 E Switch, same script is applicable to Cisco routers as well.

Step 1

Enable TCL in your Cisco router or a Cisco Switch by using a “tclsh” command

ITKE-SW01#tclsh

Step 2

Write to script to ping hosts starting from 10.0.0.1 to 10.0.0.10 using the following script, start the script by using “foreach VAR {” followed by the IP Address of the hosts you want to ping and close the script by using following stings “} { puts [exec "ping $VAR"] }” as demonstrated below ( you can use notepad to prepare the script and then execute in your Cisco device)

foreach VAR {

10.0.0.1

10.0.0.2

10.0.0.3

10.0.0.4

10.0.0.5

10.0.0.6

10.0.0.7

10.0.0.8

10.0.0.9

10.0.0.10

} { puts [exec "ping $VAR"] }

Once you enter the script you will the following

TCL scripts are very helpful and really it automates some of our tasks.

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ITKE-SW01#tclsh

If the Cisco Router or a Cisco Ctalyst Switch supports the TCL feature you will see the following prompt in your device

ITKE-SW01(tcl)#

In the above example I just demonstrated how to enable the feature in a Cisco Router or a Cisco Catalyst Switch. In order to quit from the tcl mode you can use the “tclq” command as shown below.

ITKE-SW01(tcl)#tclq

ITKE-SW01#

In my next post I will try to post few examples for usage of TCL scripts.

In today’s World we have many written scripts to automate our common tasks at work, we quite often use scripts in programming language, Linux, UNIX or even windows. But when it comes to networking to be more specific on Cisco devices there was no scripting language. However Cisco Systems realized the importance of automating the things and they come adding the “Tool Command Language in short TCL in Cisco IOS. This feature is enabled in the IOS starting from 12.3(2) T. I know most of us are not aware of this powerful scripting language.

TCL is a very powerful dynamic scripting language and it is based on open programming language developed by John Ousterhout.

Infact Cisco Press come out with a title named TCL Script for Cisco IOS which was released on June 9, 2010.

In upcoming articles I will try to address TCL commands how it can enabled and some sample scripts which can be used in day to day networking activities on Cisco Routers and Cisco Catalyst Switches.