FreeCommander

After activating the main menu item "File → View external" or the "Shift+F3" key the contents of the item (file or folder) highlighted in the active panel is displayed by an external viewer.

Under the main menu item "Tools → Settings → Programs" in the tab "External viewers", the user may define programs for displaying the contents of items (files or folders), depending on their file extension. On activation of the menu item "File → View external" or the shortcut "Shift+F3", the filters listed in these settings are analyzed sequentially from the top down. The highlighted file is opened by the external viewer assigned to the first matching filter. If no external viewer is defined or no filter matches the highlighted item, it will not be shown.

External viewers are defined independently of the "normal" viewers (defined under the main menu item "Tools → Settings → Programs" in the tab "Viewers" and opened with the menu item "File → View".