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Tk GUI to provide system state reporting box
First Widgets, Geometry and Events example from a Well House Consultants training course
More on First Widgets, Geometry and Events [link]

This example is described in the following article(s):
   • A new Tcl/tk example - a window to show system status - [link]

Source code: admin Module: T217
#!/usr/bin/env tclsh

# Tk GUI to provide system state reporting box

package require Tk

set actions {
        { {} {date} {(.+)\n} }
        { {system name} {uname -n} {(\S+)} }
        { {job q, 1 minute} {uptime} {(\d+\.\d+)} }
        { {ip address} {ifconfig -a} {.*inet\s+(\S+)}}
        { {disc usage} {df -k} {(\d+%)} }

proc downdate {what {mode auto}} {
        upvar $what actions
        for {set k 0} {$k < [llength $actions]} {incr k} {
                global say$k

                set record [lindex $actions $k]
                set basetext [lindex $record 0]
                set myCommand [lindex $record 1]
                set myFilter [lindex $record 2]

                set gotten [perform $myCommand $myFilter]

                if {$basetext == ""} {
                        set say$k $gotten
                } else {
                        set say$k "$basetext ---- $gotten"
        if {$mode == "interactive"} {
                if {[.pushme cget -text] == "Freeze"} {
                        .pushme configure -text "Thaw"
                } else {
                        .pushme configure -text "Freeze"

        # re-run the update proc in 1 second if not frozen at present
        if {[.pushme cget -text] == "Freeze"} {
                after 1000 "downdate actions"

# proc to run a system command and return an expression from the result

proc perform {this lookfor} {
        set pipehandle [open "| $this" "r"]
        set stuff [read $pipehandle]
        regexp $lookfor $stuff all some
        close $pipehandle
        return $some

# ---------------- Main action code. Make and pack buttons and labels

for {set k 0} {$k < [llength $actions]} {incr k} {
        label .say$k -textvariable say$k
        pack .say$k
        set say$k default

# should have been "update" but there's one in Tcl already!
pack [button .pushme -text "Freeze" -command "downdate actions interactive"]
pack [button .done -text "exit" -command exit]

# Start off by calculating initial values by running "button pressed" code

downdate actions

# And enter event loop (no code for that!)
Learn about this subject
This module and example are covered on the following public courses:
 * Learning to program in Tcl
 * Tcl/Tk
 * Tcl Programming
Also available on on site courses for larger groups

Books covering this topic
Yes. We have over 700 books in our library. Books covering Tcl, Tk and Expect are listed here and when you've selected a relevant book we'll link you on to Amazon to order.

Other Examples
This example comes from our "First Widgets, Geometry and Events" training module. You'll find a description of the topic and some other closely related examples on the "First Widgets, Geometry and Events" module index page.

Full description of the source code
You can learn more about this example on the training courses listed on this page, on which you'll be given a full set of training notes.

Many other training modules are available for download (for limited use) from our download centre under an Open Training Notes License.

Other resources
• Our Solutions centre provides a number of longer technical articles.
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This web site is written and maintained by Well House Consultants.

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This is a sample program, class demonstration or answer from a training course. It's main purpose is to provide an after-course service to customers who have attended our public private or on site courses, but the examples are made generally available under conditions described below.

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