Opgelost! Even goed nadenken en nog een keer lezen en 't is gelukt.
Wat de "fout" was die er voor zorgde dat er nog steeds full backups gedraaid werden is dat de file server-last-full als aanduiding "12-mrt" had. Dat heb ik aangepast naar "12-Mar", script laten lopen en het werkt perfect.
Hartelijk dank aan Dennis en kennywest die me in meerdere topics geholpen hebben
Voor diegenen die er ook gebruik van willen maken, hier is het (werkende) script:
#!/bin/sh
# full and incremental backup script
# created 07 February 2000
# Based on a script by Daniel O'Callaghan
# and modified by Gerhard Mourani
# Adjust date format for your locale
export LOCALE=C
export LC_ALL=C
# Change the 5 variables below to fit your computer/backup
COMPUTER=[servernaam] # name of this computer
DIRECTORIES="[te backuppen directories]" # directories to backup
BACKUPDIR=[backup directory] # where to store the backups
TIMEDIR=[backup directory]/last-full # where to store time of full backup
TAR=/bin/tar # name and location of tar
# You should not have to change anything below here
PATH=/usr/local/bin:/usr/bin:/bin
DOW=`date +%a` # Day of the week e.g. Mon
DOM=`date +%d` # Date of the Month e.g. 27
DM=`date +%d%b` # Date and Month e.g. 27Sep
# On the 1st of the month a permanent full backup is made
# Every Sunday a full backup is made - overwriting last Sunday's backup
# The rest of the time an incremental backup is made. Each incremental
# backup overwrites last week's incremental backup of the same name.
#
# if NEWER = "", then tar backs up all files in the directories
# otherwise it backs up files newer than the NEWER date. NEWER
# gets it date from the file written every Sunday.
# Monthly full backup
if [ $DOM = "01" ]; then
NEWER=""
$TAR $NEWER -cf $BACKUPDIR/$COMPUTER-$DM.tar $DIRECTORIES
echo "Maandelijkse volledige backup $DM" >> /var/log/script.log
fi
# Weekly full backup
if [ $DOW = "Sun" ]; then
NEWER=""
NOW=`date +%d-%b`
# Update full backup date
echo $NOW > $TIMEDIR/$COMPUTER-full-date
$TAR $NEWER -cf $BACKUPDIR/$COMPUTER-$DOW.tar $DIRECTORIES
echo "Wekelijkse volledige backup $DM" >> /var/log/script.log
# Make incremental backup - overwrite last weeks
else
# Get date of last full backup
NEWER="--newer `cat $TIMEDIR/$COMPUTER-full-date`"
$TAR $NEWER -cf $BACKUPDIR/$COMPUTER-$DOW.tar $DIRECTORIES
echo "Dagelijkse incrementele backup $DM" >> /var/log/script.log
fi