volts

#!/usr/bin/env bash

#######################################################################
# Made by    : Ewoud Dronkert
# Licence    : GNU GPL v3
# Platform   : Raspberry Pi
# Requires   : Raspbian, bash, vcgencmd
# Location   : ~/bin/
# Name       : volts
# Version    : 1.1.0
# Date       : 2022-10-06
# Purpose    : Print formatted list of voltage measurements on the RPi
# Parameters : none
# Settings   : none
# Exit       : no exit codes used
#######################################################################

# Look up decimal separator for given locale
function GetSep() {
	[ -z "$1" ] && return 1
	DEFFILE="/usr/share/i18n/locales/$1"
	[ ! -f "$DEFFILE" ] && return 2
	[ ! -r "$DEFFILE" ] && return 3
	SYMBOL=$(cat "$DEFFILE" | grep ^decimal_point | awk '{print $2}' | sed -E 's/^"|"$//g')
	if [ "${SYMBOL:0:2}" == "<U" ]; then
		UNICODE=$(echo "$SYMBOL" | sed -E 's/^<|>$//g')
		echo -ne "\\$UNICODE"
	else
		echo -n "$SYMBOL"
	fi
	return 0
}

# Determine POSIX decimal separator which 'vcgencmd' uses in output
# TODO: check error code return
DOT=$(GetSep 'POSIX')

# Determine current locale decimal separator which 'printf' expects as input
LCN="$LC_ALL"
[ -z "$LCN" ] && LCN="$LC_NUMERIC"
[ -z "$LCN" ] && LCN=$(locale | grep ^LC_NUMERIC | cut -d= -f2 | sed -e 's/"//g')
# Use only the part of LCN before the dot
# TODO: check error code return
SEP=$(GetSep "${LCN%%.*}")
[ -z "$SEP" ] && SEP=$DOT

# Measure voltage at different points
for PROBE in core sdram_c sdram_i sdram_p; do

	# Get measurement, select part after '='
	VOLT=$(vcgencmd measure_volts $PROBE | cut -d= -f2)

	# Remove trailing 'V', result is float #.#####
	VOLT=${VOLT%V}

	# Replace decimal separator if needed
	[ "$SEP" != "$DOT" ] && VOLT=${VOLT/$DOT/$SEP}

	# Formatted output
	printf '%-8s:%6.3f\n' "$PROBE" "$VOLT"

done
exit 0