If no association use: Enter the default viewer to use when: a) a file has no Windows file association on your computer or b) when you select the Search & Replace default viewer. You may also use the Browse button () to select a default viewer via the Select Viewer dialog. Search and Replace can pass the following variables on the command line:

%path% - Full file path to the file

%line% - Line number of the search hit.

See External Editors for more information and some sample command lines.