The filter bar is a small text field that pops up at the bottom of the file display, and makes it easy to quickly filter the current file list. By default you press * to display the filter bar, although this key can be modified through the File Displays / Quick Keys Preferences page.
The filter bar appears as soon as you press the activation key and you can continue typing immediately to begin filtering the list.
In the above screenshot, we have filtered the C:\Windows\System32 directory to show all files that end in .msc. You can see from the status bar that this resulted in 4,671 items being hidden from the display, leaving only 21 .msc files visible.
The filter bar displays these statistics as well, in slightly more detail (it breaks the hidden item count into hidden files and hidden folders).
The filter bar affects what is called the "quick filter". This filter is applied on top of the filters set via the Folder Formats system, and the global filtering options on the Global Filters Preferences page. It doesn't override these filters - so any files hidden via these other methods will stay hidden no matter what the quick filter is set to.
To clear the filter, press Esc or click the X button on the filter bar.
By default the filter bar will disappear automatically when the filter is cleared, but there's an option on the Filter Bar Preferences page to keep it open all the time if you prefer.
You can configure the file display to display a different background color whenever the quick filter is active, using the File display background settings on the Directory Opus Colors page in Preferences.
The "file" and "folder" icons on the filter bar that show the file and folder totals are clickable:
The options button shows a menu that lets you control how the filter is applied:
Use the Save as default command to save the current settings as the defaults.
The filetypes button shows a menu that lets you quickly filter by file extension or filetype group, based on the actual contents of the folder.
The top part of the menu refers to filetype groups - in this example, there is one file from the Documents group, five from the Images group, and so on.
The bottom part of the menu lists the file extensions that appear in the current folder.
Select a group or extension from the menu to quickly filter on that type (you can also select more than one at once).
You can display the filetype menu from the keyboard by pressing Shift+F5 when the cursor is on the filter field.
The Show everything option provides a quick toggle for the Show Everything mode - a way to temporarily disable filters and display all files and folders in the current folder.
When the file display you are filtering is in Flat View mode the Filter folders in Flat view option appears.
This lets you control whether the filter applies to folders or only to files. When a folder is filtered out of the display in Flat View mode, all files within that folder (and its sub-folders) are also filtered out. This behavior may or may not be desirable and it can be confusing to have a whole lot of files suddenly disappear unexpectedly, which is which this option is available (and off by default).
The default state of this option can be changed by modifying the flatview_folder_filters option on the Miscellaneous / Advanced page in Preferences.
With the Evaluator option turned on, the Filter Bar uses the Evaluator to evaluate the expression you provide. This can be used in two ways:
If the pre-defined filter uses the evaluator as well, the Filter Bar can pass arguments to it. For example, ?bigfiles:5 would pass the value 5 through to the evaluation clause defined in the filter.
See Evaluator Contexts - Filters and Find for more information.
You can also use the find-as-you-type field for quick filtering (although it doesn't have the additional functionality the filter bar does).
To do this you need to assign an activation key for the Filter mode on the Quick Keys Preferences page. See the documentation for the find-as-you-type field for more information on this.