Notepad++: Multiple words search in a file (may be in different lines)?

You need a new version of notepad++. Looks like old versions don't support |.

Note: egrep "CAT|TOWN" will search for lines containing CATOWN. (CAT)|(TOWN) is the proper or extension (matching 1,3,4). Strangely you wrote and which is btw (CAT.*TOWN)|(TOWN.*CAT)

Possible solution

1. In Notepad++ , click search menu, the click Find
2. in FIND WHAT : enter this ==> cat|town
3. Select REGULAR EXPRESSION radiobutton
4. click FIND IN CURRENT DOCUMENT

Screenshot