Replacing blank tags

I'd like to replace all blank disc numbers with a one, but am unable to figure out how to match a blank...
In vi i'd just use
^$ but this doesn't seem to work. How can I pattern match a blank field?


You can use a different action type:

Action type: Format value
Format string: $if2(%discnumber%,1)

which means if %discnumber% has already a value, keep it. If not set it to 1.

Thank you.