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Full Discussion: Need help with repeating variables in a shell script
Top Forums UNIX for Dummies Questions & Answers Need help with repeating variables in a shell script Post 302760697 by ricco19 on Thursday 24th of January 2013 12:17:11 PM
Old 01-24-2013
Need help with repeating variables in a shell script
I should preface this by saying I have never worked with shell scripts before so this is all new to me. I was able to make something that worked, but is terribly optimized, and I have no idea how to improve it. If anything it's a pretty hilarious script:

Code:
   #/bin/bash
    
    get_char() {
    	old_tty_settings=`stty -g`
    	stty -icanon min 0 time 1
    	stty cbreak
    	grabbed_char=`dd if=/dev/tty bs=1 count=1 2>/dev/null`
    	stty -cbreak
    	stty "$old_tty_settings"
    }
    
    while true; do
    
    	unset char00
    	unset char01
    	unset char02
    	unset char03
    	unset char04
    	unset char05
    
    	echo -e "\nWaiting for keystroke..."
    	read -n 1 char00
    
    	while true; do
    
    		get_char; char01=$grabbed_char
    
    		if [ "$char01" != "" ]; then get_char; char02=$grabbed_char
    			else break
    		fi
    		if [ "$char02" != "" ]; then get_char; char03=$grabbed_char
    			else break
    		fi
    		if [ "$char03" != "" ]; then get_char; char04=$grabbed_char
    			else break
    		fi
    		if [ "$char04" != "" ]; then get_char; char05=$grabbed_char
    			else break
    		fi
    
    	done
    
    	fullstring=$char00$char01$char02$char03$char04$char05
    	echo -e "\nFULLSTRING:	!$fullstring!"
    
    done


The list is a lot longer, but I spared you.

Basically, the program needs to sit in terminal forever waiting for a keystroke. After an initial keystroke, it needs to wait a very short amount of time (1/10th of a second in this case) for another keystroke. If no keystroke is registered in that short time, it echos the output (which will be piped with sed commands), and restarts.

It is meant to be used with a barcode scanner, where you may scan 4 characters, or 100 characters. We want to process the data as quickly as possible, meaning we don't want a 1 second delay after something is scanned.

A good solution would be if "charXX" could be created as a character was received. Thanks for any help.
 

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LEARN ABOUT DEBIAN

lr_environment

LR_ENVIRONMENT.IN(1)					  LogReport's Lire Documentation				      LR_ENVIRONMENT.IN(1)

NAME

       lr_environment - Export Lire configuration in shell script form

SYNOPSIS

       eval `lr_environment`

DESCRIPTION

       The lr_environment command is used to import the Lire configuration in Lire shell scripts.

       All of Lire configuration variables will be written in a format that can be evaled by the shell.

       Shell scripts don't usually have to use that command, since it is done by the defaults file sourced by each command.

       The old names used by when the configuration was done in shell script are also exported by this script for backward compatibility.

AUTHOR

	 Francis J. Lacoste <flacoste@logreport.org>

VERSION

       $Id: lr_environment.in,v 1.12 2006/07/23 13:16:33 vanbaal Exp $

COPYRIGHT

       Copyright (C) 2003 Stichting LogReport Foundation LogReport@LogReport.org

       This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by
       the Free Software Foundation; either version 2 of the License, or (at your option) any later version.

       This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
       MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more details.

       You should have received a copy of the GNU General Public License along with this program (see COPYING); if not, check with
       http://www.gnu.org/copyleft/gpl.html.

Lire 2.1.1							    2006-07-23						      LR_ENVIRONMENT.IN(1)
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