script..

#! /bin/sh

TO_REPLEACE="/usr/local/etc/squirrelmail/ariel.insert"

if [ -d /usr/local/etc/squirrelmail/dataTEST/data ]
then
        # mi copia
        cd /usr/local/etc/squirrelmail/dataTEST/data
else
        # nada
        cd /dev/null
fi

find . -type f -name '*.pref' -print | while read i
do
        cp "$i" "$i.tmp"
        if [ -f "$i.tmp" ]
        then
                cat $TO_REPLEACE >> $i.tmp
                cp $i.tmp /usr/local/etc/squirrelmail/final/$i
                else
                        echo "$i.new doesn't exist"
                fi
done