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Full Discussion: sh: Detect key (CTRL/SHIFT/CAPS LOCK) state?
Top Forums Shell Programming and Scripting sh: Detect key (CTRL/SHIFT/CAPS LOCK) state? Post 302487209 by methyl on Tuesday 11th of January 2011 04:54:26 PM
Old 01-11-2011
Clearly /dev/input/event3 is not a text file and therefore not suitable for reading with a Shell read. In fact there is little of interest to Shell programmers under /dev. (Yep I know about /dev/null etc.).
Be very very careful in /dev - it is remarkably easy to destroy your system.

What is the output from:
Code:
ls -lad /dev/input/event3
file /dev/input/event3

(Googling the device suggests that it might be a keyboard device on some versions of Linux - a fact of little use to Shell programmers).

What Operating System and version are you running?
What Shell are you running?
What are you trying to do? Can you explain the Project in words just in case there is a stock solution?


There will be kernel driver software between Shell and a keyboard.
If you have "bash" there is a Shell raw "read" with a timeout but even then it will not register keys like ctrl and shift as characters. Reading characters in a tight loop without timeout is CPU-intensive.

A common way to modify the behaviour of a cleverly designed running Shell script is to create a flag file or to use a Shell "trap" to react to a keyboard control code or signal.


What is an "initramfs script", what does it do, and why would you want to interrupt it?

Is it like this:
http://en.wikipedia.org/wiki/Initrd

What runstate are you in while this script is running?
Last edited by methyl; 01-11-2011 at 06:05 PM.. Reason: addenda, grammar, afterthoughts, etc.
 

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LEARN ABOUT CENTOS

cpanplus::shell

CPANPLUS::Shell(3)					User Contributed Perl Documentation					CPANPLUS::Shell(3)

NAME

       CPANPLUS::Shell - base class for CPANPLUS shells

SYNOPSIS

	   use CPANPLUS::Shell; 	    # load the shell indicated by your
					    # config -- defaults to
					    # CPANPLUS::Shell::Default

	   use CPANPLUS::Shell qw[Classic]  # load CPANPLUS::Shell::Classic;

	   my $ui      = CPANPLUS::Shell->new();
	   my $name    = $ui->which;	    # Find out what shell you loaded

	   $ui->shell;			    # run the ui shell

DESCRIPTION

       This module is the generic loading (and base class) for all "CPANPLUS" shells. Through this module you can load any installed "CPANPLUS"
       shell.

       Just about all the functionality is provided by the shell that you have loaded, and not by this class (which merely functions as a generic
       loading class), so please consult the documentation of your shell of choice.

BUG REPORTS

       Please report bugs or other issues to <bug-cpanplus@rt.cpan.org<gt>.

AUTHOR

       This module by Jos Boumans <kane@cpan.org>.

COPYRIGHT

       The CPAN++ interface (of which this module is a part of) is copyright (c) 2001 - 2007, Jos Boumans <kane@cpan.org>. All rights reserved.

       This library is free software; you may redistribute and/or modify it under the same terms as Perl itself.

SEE ALSO

       CPANPLUS::Shell::Default, CPANPLUS::Shell::Classic, cpanp

perl v5.16.3							    2013-05-20							CPANPLUS::Shell(3)
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