TCL (Tool Command Language)

TCL is an open source scripting language. It is incorporated into cisco ios routers operating system and is available on many other vendors’ networking devices.

There are three primary reasons why network administrator should learn it. If network admins have a firm hand on tcl is definitely a VAS (Value Added Skill).

  1. Better Automation
  2. Increased Security
  3. Remote Command Line Applications

Example:

This tcl example will test connectivity between routers with ping command. The ping command is embedded inside this simple tcl script.

AccessServer#tclsh
AccessServer(tcl)#
AccessServer(tcl)#foreach address {
+>192.168.1.2
+>192.168.2.1
+>192.168.2.2
+>192.168.3.1
+>192.168.3.2
+>} { ping $address }

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 192.168.1.2, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 16/31/60 ms
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 192.168.2.1, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 8/24/44 ms
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 192.168.2.2, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 16/38/52 ms
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 192.168.3.1, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 24/42/56 ms
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 192.168.3.2, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 36/56/84 ms
AccessServer(tcl)#exit

AccessServer#

Resources:

TCL Home Page

Documentation and Demos

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