[NaLug] [mini-HOWTO] utilizzare i tasti per il controllo del volume sulle tastiere con tasti speciali

[ncrfgs a tin.it]

#!/bin/bash
#
#  ctrltgl.sh
#
#  Copyright (c) 2008 Fergus Incoronato
#
#  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; if not, write to the Free Software
#  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, 
#  USA.
#

info() {
	echo "=======> $1"
}

warning() {
	info "WARNING: $1" >&2
}

error() {
	info "ERROR: $1" >&2
}

interrupted() {
	echo ""
	error "Interrupted."
	exit 1
}

parse_options() {
	if (($#<5)); then
		echo "`basename $CTRLTGL_COMMAND`: not enough arguments"
		exit 1  
	elif (($#>5)); then
		echo "`basename $CTRLTGL_COMMAND`: too many arguments"
		exit 1  
	fi

	while [ "$1" ]; do
		case $1 in
			set|sset)
				if [ ! "$2" ]; then
					echo "`basename $CTRLTGL_COMMAND`: Specify a scontrol identifier: 'name',index"
					exit 1
				elif [ ! "$3" ]; then
					echo "`basename $CTRLTGL_COMMAND`: Specify what you want to set..."
					exit 1
				fi
				SCONTROL="$2"
				OVFILE="$2.state"
				PARAMETER="$3"
				shift
				shift ;;
			-d|--directory)
				if [ ! "$2" ]; then
					echo "`basename $CTRLTGL_COMMAND`: option $1 requires an argument"
					exit 1
				fi
				WORK_DIR="$2"
				shift ;;
			*)
				echo "`basename $CTRLTGL_COMMAND`: invalid option $1"
				exit 1 ;;
		esac
		shift
	done
}

check_exists() {
	if [ ! -e "$1" ]; then
		error "'$1' does not exist."
		exit 1
	fi
}

check_is_directory() {
	if [ ! -d "$1" ]; then
		error "'$1' is not a directory."
		exit 1
	fi
}

check_is_regular() {
	if [ ! -f "$1" ]; then
		error "'$1' is not a regular file."
		exit 1
	fi
}

check_is_writable() {
	if [ ! -w "$1" ]; then 
		error "'$1' is not writable."
		exit 1
	fi
}

check_is_readable() {
	if [ ! -r "$1" ]; then
		error "'$1' is not readable."
		exit 1
	fi
}

toggle_volume() {
	if ((CUR_VOL!=MIN)) || [ ! "$OLD_VOL" ]; then
		NEW_VOL="$MIN"
	else
		CUR_VOL=""
		NEW_VOL="$OLD_VOL"
	fi	
}

mute_volume() {
	NEW_VOL="$MIN"
        if [ "$OLD_VOL" ]; then
		CUR_VOL="$OLD_VOL"
	fi
}

unmute_volume() {
	if [ ! "$OLD_VOL" ]; then
		NEW_VOL="$CUR_VOL"
	else
		NEW_VOL="$OLD_VOL"
	fi
	CUR_VOL=""
}

lower_volume() {
	if [ ! "$OLD_VOL" ]; then
		NEW_VOL=$((CUR_VOL-${PARAMETER%-}))
		if ((NEW_VOL<MIN)); then NEW_VOL="$MIN"; fi
		CUR_VOL="$OLD_VOL"
	else
		NEW_VOL="$CUR_VOL"
		CUR_VOL=$((OLD_VOL-${PARAMETER%-}))
		if ((CUR_VOL<MIN)); then CUR_VOL="$MIN"; fi
	fi
}

raise_volume() {
	if [ ! "$OLD_VOL" ]; then
		NEW_VOL=$((CUR_VOL+${PARAMETER%+}))
		if ((NEW_VOL>MAX)); then NEW_VOL="$MAX"; fi
		CUR_VOL="$OLD_VOL"
	else
		NEW_VOL="$CUR_VOL"
		CUR_VOL=$((OLD_VOL+${PARAMETER%+}))
		if ((CUR_VOL>MAX)); then CUR_VOL="$MAX"; fi
	fi
}

main() {
	local SCONTROL OVFILE PARAMETER WORK_DIR OVFILE_SIZE NUMID MIN MAX OLD_VOL CUR_VOL NEW_VOL

	parse_options "$@"

	check_exists "$WORK_DIR"
	check_is_directory "$WORK_DIR"
	check_is_writable "$WORK_DIR"
	check_is_readable "$WORK_DIR"

	check_exists "$WORK_DIR/$OVFILE"
	check_is_regular "$WORK_DIR/$OVFILE"
	check_is_writable "$WORK_DIR/$OVFILE"
	check_is_readable "$WORK_DIR/$OVFILE"

	OVFILE_SIZE="`find "$WORK_DIR/$OVFILE" -printf "%s\n"`"

	if ((OVFILE_SIZE<1)) || ((OVFILE_SIZE>4)); then
		error "'$WORK_DIR/$OVFILE' size is incompatible with allowed values."
		exit 1
	fi

	NUMID="`amixer controls | grep "$SCONTROL" | cut -d , -f 1 | cut -d = -f 2`"
	MIN="`amixer cget numid="$NUMID" | grep ';' | cut -d , -f 4 | cut -d = -f 2`"
	MAX="`amixer cget numid="$NUMID" | grep ';' | cut -d , -f 5 | cut -d = -f 2`"
	
	OLD_VOL="`cat "$WORK_DIR/$OVFILE"`"
	CUR_VOL="`amixer cget numid="$NUMID" | grep : | cut -d , -f 2`"

	if [ "$OLD_VOL" ]; then
		if ((CUR_VOL!=MIN)); then
			sed "1s|^$OLD_VOL$||" -i "$WORK_DIR/$OVFILE"
			OLD_VOL=""
		elif ((OLD_VOL<MIN)); then
			sed "1s|^$OLD_VOL$|$MIN|" -i "$WORK_DIR/$OVFILE"
			OLD_VOL="$MIN"
		elif ((OLD_VOL>MAX)); then
			sed "1s|^$OLD_VOL$|$MAX|" -i "$WORK_DIR/$OVFILE"
			OLD_VOL="$MAX"
		fi
	fi

	case $PARAMETER in
		toggle)
			toggle_volume ;;
		mute)
			mute_volume ;;
		unmute)
			unmute_volume ;;
		*[[:digit:]]-)
			lower_volume ;;
		*[[:digit:]]+)
			raise_volume ;;
		*)
			echo "`basename $CTRLTGL_COMMAND`: invalid parameter $PARAMETER"
			exit 1 ;;
	esac

	sed "1s|^$OLD_VOL$|$CUR_VOL|" -i "$WORK_DIR/$OVFILE"

	amixer sset "$SCONTROL" "$NEW_VOL"

	exit 0
}

trap "interrupted" SIGHUP SIGINT SIGQUIT SIGTERM

readonly CTRLTGL_VERSION="0.2.30"
readonly CTRLTGL_COMMAND="$0"

main "$@"

# End of file
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