geometry, tk_library, tk_patchLevel, tk_strictMotif, tk_version − Variables used or set by Tk ___________________________


The following Tcl variables are either set or used by Tk at various times in its execution:


This variable holds the file name for a directory containing a library of Tcl scripts related to Tk. These scripts include an initialization file that is normally processed whenever a Tk application starts up, plus other files containing procedures that implement default behaviors for widgets.

The initial value of tcl_library is set when Tk is added to an interpreter; this is done by searching several different directories until one is found that contains an appropriate Tk startup script. If the TK_LIBRARY environment variable exists, then the directory it names is checked first. If TK_LIBRARY is not set or does not refer to an appropriate directory, then Tk checks several other directories based on a compiled-in default location, the location of the Tcl library directory, the location of the binary containing the application, and the current working directory.

The variable can be modified by an application to switch to a different library.


Contains a dot-separated sequence of decimal integers giving the current patch level for Tk. The patch level is incremented for each new release or patch, and it uniquely identifies an official version of Tk.

This value is normally the same as the result of “package require Tk”.


This variable is set to zero by default. If an application sets it to one, then Tk attempts to adhere as closely as possible to Motif look-and-feel standards. For example, active elements such as buttons and scrollbar sliders will not change color when the pointer passes over them. Modern applications should not normally set this variable.


Tk sets this variable in the interpreter for each application. The variable holds the current version number of the Tk library in the form major.minor. Major and minor are integers. The major version number increases in any Tk release that includes changes that are not backward compatible (i.e. whenever existing Tk applications and scripts may have to change to work with the new release). The minor version number increases with each new release of Tk, except that it resets to zero whenever the major version number changes.

These variables should not normally be set by user code.

This variable is an array containing several pieces of information that are private to Tk. The elements of tk::Priv are used by Tk library procedures and default bindings. They should not be accessed by any code outside Tk.


These variables are set by text widgets when they have debugging turned on. The values written to these variables can be used to test or debug text widget operations. These variables are mostly used by Tk’s test suite.


The following variables are only guaranteed to exist in wish executables; the Tk library does not define them itself but many Tk environments do.

If set, contains the user-supplied geometry specification to use for the main Tk window.


package(n), tclvars(n), wish(1)


environment, text, variables, version


Personal Opportunity - Free software gives you access to billions of dollars of software at no cost. Use this software for your business, personal use or to develop a profitable skill. Access to source code provides access to a level of capabilities/information that companies protect though copyrights. Open source is a core component of the Internet and it is available to you. Leverage the billions of dollars in resources and capabilities to build a career, establish a business or change the world. The potential is endless for those who understand the opportunity.

Business Opportunity - Goldman Sachs, IBM and countless large corporations are leveraging open source to reduce costs, develop products and increase their bottom lines. Learn what these companies know about open source and how open source can give you the advantage.

Free Software

Free Software provides computer programs and capabilities at no cost but more importantly, it provides the freedom to run, edit, contribute to, and share the software. The importance of free software is a matter of access, not price. Software at no cost is a benefit but ownership rights to the software and source code is far more significant.

Free Office Software - The Libre Office suite provides top desktop productivity tools for free. This includes, a word processor, spreadsheet, presentation engine, drawing and flowcharting, database and math applications. Libre Office is available for Linux or Windows.

Free Books

The Free Books Library is a collection of thousands of the most popular public domain books in an online readable format. The collection includes great classical literature and more recent works where the U.S. copyright has expired. These books are yours to read and use without restrictions.

Source Code - Want to change a program or know how it works? Open Source provides the source code for its programs so that anyone can use, modify or learn how to write those programs themselves. Visit the GNU source code repositories to download the source.


Study at Harvard, Stanford or MIT - Open edX provides free online courses from Harvard, MIT, Columbia, UC Berkeley and other top Universities. Hundreds of courses for almost all major subjects and course levels. Open edx also offers some paid courses and selected certifications.

Linux Manual Pages - A man or manual page is a form of software documentation found on Linux/Unix operating systems. Topics covered include computer programs (including library and system calls), formal standards and conventions, and even abstract concepts.