[gelöst] XOR Checksumme von String in Bash berechnen

#!/bin/bash

#Schnittstellenparameter setzen
stty -F /dev/ttymxc0 9600 cs8 -cstopb

while true;
do
    before=$(mpc -h localhost -f "%title% %artist%" current)
    after=$(mpc -h localhost -f "%title% %artist%" current)
    while [ "$before" = "$after" ];
    do
      after=$(mpc -h localhost -f "%title% %artist%" current)
      #echo aktualisieren
      sleep 5
    done
    message=$(mpc -h localhost -f "%title% von %artist%" current)
    echo "<ID00><L1><PB><FA><MC><WA><FA>$message(Hier die Checksumme mit 2 Byte)<E>"  > /dev/ttymxc0
    echo "Übertragung beendet: $message"
done

echo $message | perl -wnle 'print 0xff ^ unpack "%8C*", pack"H*", $_'

# $value=checksum($string)
# Calculates a string's checksum
#
# Parameters:
#   $string     : string to checksum
#
# Returns:
#   $value      : checksum, integer 0..255
#
sub checksum{
	my($string)=@_;
	return(undef) unless(defined($string));
	my $value=0;
	my $i;
	for($i=0; $i < length($string); $i++){
		$value=$value^ord(substr($string,$i,1));
	}
	return($value);
}

echo "Hallo"| perl -lne '$v=0;for$i(0..length){$v=$v^ord(substr($_,$i,1))}print$v'