Here's the completed script (the IP/CIDR extract worked perfectly -- thanks Barney!):
--- #!/bin/sh ORIGINAL=/usr/local/etc/postfix/tables/client_access_maps.cidr NEW=/tmp/postfix_clients.tmp dig +short senderdomain.net TXT | grep 'v=spf1' | egrep -o 'ip4:[0-9./]+' | sed 's/^ip4://' | sed 's/$/ OK/' > $NEW ORIGINAL_CK=`cksum $ORIGINAL | awk '{print $1}'` NEW_CK=`cksum $NEW | awk '{print $1}'` if [ -s $NEW ] ; then if [ $ORIGINAL_CK != $NEW_CK ] ; then cp -f $NEW $ORIGINAL postfix reload > /dev/null fi fi rm $NEW exit 0 --- It works except that the Postfix refresh message ("postfix/postfix-script: refreshing the Postfix mail system") is displayed despite of the attempt to redirect it to /dev/null? Any idea how I could hide it? Ville