Provided by: tk8.6-doc_8.6.13-2_all 
NAME
console - Control the console on systems without a real console
SYNOPSIS
console subcommand ?arg ...?
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DESCRIPTION
The console window is a replacement for a real console to allow input and output on the
standard I/O channels on platforms that do not have a real console. It is implemented as
a separate interpreter with the Tk toolkit loaded, and control over this interpreter is
given through the console command. The behaviour of the console window is defined mainly
through the contents of the console.tcl file in the Tk library. Except for TkAqua, this
command is not available when Tk is loaded into a tclsh interpreter with “package require
Tk”, as a conventional terminal is expected to be present in that case. In TkAqua, this
command is disabled when there is a startup script and stdin is /dev/null (as is the case
e.g. when a bundled application embedding Tk is started by the macOS Launcher). To enable
the command in that case, define the environment variable TK_CONSOLE. This can be done by
modifying the Info.plist file by adding the LSEnvironment key to the main dict and setting
its value to be a dict with the key TK_CONSOLE.
console eval script
Evaluate the script argument as a Tcl script in the console interpreter. The
normal interpreter is accessed through the consoleinterp command in the console
interpreter.
console hide
Hide the console window from view. Precisely equivalent to withdrawing the .
window in the console interpreter.
console show
Display the console window. Precisely equivalent to deiconifying the . window in
the console interpreter.
console title ?string?
Query or modify the title of the console window. If string is not specified,
queries the title of the console window, and sets the title of the console window
to string otherwise. Precisely equivalent to using the wm title command in the
console interpreter.
ACCESS TO THE MAIN INTERPRETER
The consoleinterp command in the console interpreter allows scripts to be evaluated in the
main interpreter. It supports two subcommands: eval and record.
consoleinterp eval script
Evaluates script as a Tcl script at the global level in the main interpreter.
consoleinterp record script
Records and evaluates script as a Tcl script at the global level in the main
interpreter as if script had been typed in at the console.
ADDITIONAL TRAP CALLS
There are several additional commands in the console interpreter that are called in
response to activity in the main interpreter. These are documented here for completeness
only; they form part of the internal implementation of the console and are likely to
change or be modified without warning.
Output to the console from the main interpreter via the stdout and stderr channels is
handled by invoking the tk::ConsoleOutput command in the console interpreter with two
arguments. The first argument is the name of the channel being written to, and the second
argument is the string being written to the channel (after encoding and end-of-line
translation processing has been performed.)
When the . window of the main interpreter is destroyed, the tk::ConsoleExit command in the
console interpreter is called (assuming the console interpreter has not already been
deleted itself, that is.)
DEFAULT BINDINGS
The default script creates a console window (implemented using a text widget) that has the
following behaviour:
[1] Pressing the tab key inserts a TAB character (as defined by the Tcl \t escape.)
[2] Pressing the return key causes the current line (if complete by the rules of info
complete) to be passed to the main interpreter for evaluation.
[3] Pressing the delete key deletes the selected text (if any text is selected) or the
character to the right of the cursor (if not at the end of the line.)
[4] Pressing the backspace key deletes the selected text (if any text is selected) or
the character to the left of the cursor (of not at the start of the line.)
[5] Pressing either Control+A or the home key causes the cursor to go to the start of
the line (but after the prompt, if a prompt is present on the line.)
[6] Pressing either Control+E or the end key causes the cursor to go to the end of the
line.
[7] Pressing either Control+P or the up key causes the previous entry in the command
history to be selected.
[8] Pressing either Control+N or the down key causes the next entry in the command
history to be selected.
[9] Pressing either Control+B or the left key causes the cursor to move one character
backward as long as the cursor is not at the prompt.
[10] Pressing either Control+F or the right key causes the cursor to move one character
forward.
[11] Pressing F9 rebuilds the console window by destroying all its children and
reloading the Tcl script that defined the console's behaviour.
Most other behaviour is the same as a conventional text widget except for the way that the
<<Cut>> event is handled identically to the <<Copy>> event.
EXAMPLE
Not all platforms have the console command, so debugging code often has the following code
fragment in it so output produced by puts can be seen while during development:
catch {console show}
SEE ALSO
destroy(3tk), fconfigure(3tcl), history(3tcl), interp(3tcl), puts(3tcl), text(3tk),
wm(3tk)
KEYWORDS
console, interpreter, window, interactive, output channels