Tcl/Tk Introduction: A GUI Calculator
The first Tclsh Spot article introduced the basic commands and showed how to create a GUI calculator (with 8 commands and about 30 lines of code.)

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Catching unowned IRC Robots
This article described a simple script that will confirm that all the tasks running on a system are owned by legitimate, logged in, users. We used this script to track and kill IRC Robots that crackers left on the college network where Clif Flynt was teaching at the time.

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An HTML viewer for MIME mail readers
I like to read mail with a plain old text type mail viewer. But metamail doesn't have built in support for HTML mail. This viewer will handle simple HTML messages (but not most advertising mail).

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Extending the HTML viewer
This article shows how to extend the Tcl HTML package to read images, and bounce to hyperlinks.

The example code is an improved htmlviewer that will let you look at images or load links at your discretion.

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Introducing the stock robot
This is the first of several articles that show how to build a simple stock quote retrieving robot.

This article creates a simple robot that will return the current price.

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Extending the stock robot
This article explains some of Tcl's new regular expression options, and extends the robot to get all the available data.

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Analyzing data - Introducing BLT
Now that we can get the stock data, lets start saving the results, and put together something simple to look for trends.

This article shows how to use the Tcl File commands to save the results, and how to use the BLT extension graph widget to display them later.

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More things to do with the BLT graph widget
This article expands on the previous graphing program and shows how to use bar charts with graphs, use multiple axes, and display custom labels on the tics.

Along with that, it discusses using the associative array to organize the data.

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Comparing multiple data sets with the BLT Graph widget
This article described how to:

• use BLT with multiple lines of data
• bind actions to the lines
• generate postscript images of a graph
• use a tk menubutton

It expands on the discussion from the previous three articles.

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Client/Server system monitor
Introduces the socket command, and shows how to build a client-server pair that will monitor disk space, and report when the space gets low.

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Expanded Client/Server system monitor with BLT barchart
This article expanded on the previous article by:

• Using a single server with multiple ports for different information.
• Displaying client data with a barchart.
• Handling exception conditions with catch.
• Checking for valid clients.

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Client/Server System Monitor with history
Shows how to save the last N hours worth of events, and display them in a scrolling canvas.

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Examining binary data
Describes using the binary command to dump the information in the utmp file.

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Binary data and sockets
Describes using the binary command to display the IAC interaction during the start of a telnet session.
Discusses:

• binary
• fconfigure
• read
• split
• regsub

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A simple Telnet Client
Implements a simple telnet client that can interact with a server, maintain its internal state, and respond to various commands the server can send. Demonstrates some features of the Tcl namespace.

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Display text from tcpdump output
Describes extracting the text from the hex output of tcpdump.
Discusses:

tcpdump	format	join
split	format	string	regexp

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A simple html interaction tester
An example application that takes reformatted output from tcpdump and turns it into a Tcl script that can be used to replay an interaction.
Discusses

http	vwait
clock	format	read

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Resizeable displays
Describes using pack, place and grid to make resizeable GUI applications.
Discusses:

pack

place

grid

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Scrollable Displays
Describes how to build applications with scrollbars that appear and vanish as required, and how to simulate a scrollable frame.
Discusses

frame	canvas
grid	scrollbar

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Popup Help messages
Adding popup help messages to buttons, labels, etc.
Discusses:

bind	after	toplevel
winfo	wm	message

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Firewall Validation 1: Building extensions with SWIG
Describes how to convert an existing library into a Tcl extension using swig. Builds an extension using the dnet library for sending and receiving ethernet packets.
Discusses

SWIG	extensions

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Firewall Validation 2: Testing the packet generator with AX4000
Describes using the Spirent Ax4000 to measure line usage and confirm that the dnet extension can saturate a 100-B-T line.
Discusses:

ax	interface	analyzer
enet

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Firewall Validation 3: Object Style programming in Tcl
Describes object style programming using the namespace command in the context of building broadband packets, and then describes validating the new procedures.
Discusses

namespace

variable

tcltest

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Firewall Validation 4: Capturing and Analyzing Packets with an AxTcl
How to use AxTcl on the Spirent AX-4000 to capture packets and display statistics and packet contents.
Discusses:

ax	interface	analyzer
enet

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Firewall Validation 5: Monitoring log files with Expect
Tcl's Expect extension is ideal for automated scanning log files. This article describes watching the log files to confirm that expected events occur.
Discusses

spawn

expect

exp_send

proc

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Firewall Validation 6: Client/Server sockets
Tcl's Socket interface is clean and simple. This makes it an ideal choice for developing client/server applications.
Discusses:

socket (client)	socket (server)	flush
fconfigure	fileevent	vwait

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Firewall Validation 7: Secure Sockets, TLS and creating a simple Certificate Authority
For secure applications, you need secure communications. The TLS extension allows Tcl sockets to use SSL for communications. This article describes setting up private certificates for secure private communications.
Discusses

tls::socket	tls::handshake
interp create	interpName alias

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Firewall Validation 8: Mobile Agents in Tcl
A client application can send a Tcl script an Agent server for remote evaluation. This article describes creating an Agent based client/server pair, using SSL to ensure that only scripts from trusted agents are evaluated, and evaluating scripts in a Safe sandbox.
Discusses:

safe::interpCreate	safe::interpAddToAccessPath
safe::interpDelete	info complete

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Digression: Fortran/Tcl 1: Using Tcl with FORTRAN
Adding a Tcl intepreter to a FORTRAN program is an easy way to extend your FORTRAN programs to support graphics, networks, configuration files, etc. This article describes how to link the Tcl interpreter to a FORTRAN application and use a Tk GUI for input and output.
Discusses

ftcl_start	labelframe	entry
button	label	vwait

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Digression: Fortran/Tcl 2: Making a better GUI for FORTRAN Applications
Demonstrates the flexibility of writing a GUI as script appended to a compiled application. A GUI script is easy to modify and extend without affecting the core application. You can even change a challenge/response application to a real-time application.
Discusses:

labelframe

image

scale

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FORTRAN/Tcl: Data Visualization with a Tk Canvas
FORTRAN applications can generate lots of numbers. The Tk canvas provides a good tool for visualizing that information.
Discusses

canvas	scrollbar	canvas bind
canvas xview/yview	create line	create polygon

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Wrapping applications with TOBE
In order to distribute a FORTRAN/Tcl application, either the client needs to have Tcl installed, or you need to wrap the application into a single executable. D. Richard Hipp's TOBE wrapping solution is best for this application.
Discusses

Wrapping Applications	Editing the TOBE Makefile	Tcl_Init
Tcl_EvalFile	Tcl_FindExecutable	Zip

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