# For the assigned value we only accept a limited number of characters - none
# of which are shell metachars
-VARCHARS='A-Za-z0-9=/,.:_@#+-'
+VARCHARS='A-Za-z0-9=/,.:%_@#+-'
VARVAL="[${VARCHARS}]*"
sed -ne "s/\(${VARNAME}\)=\(${VARVAL}\)$/\1=\2/p" $1