Yelp is the GNOME help viewer. It is the default Mallard viewer, but it can also display DocBook, info, man, and HTML documentation. Yelp is a good viewer for documentation with external links because complies with the freedesktop.org help system specification. It can be used easily across many Linux distributions, but may not work on other platforms, such as OS X or Windows.
Yelp has a mode for assisting authors who edit Mallard documentation. To start Yelp in editor mode, run it with the
$ yelp --editor-mode
In editor mode, Yelp shows information relevant to editors alongside elements. For instance, information from the
<revision> element is shown at the top of pages and alongside any links to those pages. Another useful addition is that editorial comments, added with the
<comment> element, are shown inline and formatted with a background that makes them highly visible.
Yelp in editor mode
An important difference when Yelp is in editor mode is that stub pages, specifically those with a file extension of
.page.stub, are included and shown in the document. When Yelp is not in editor mode, stub pages are not shown, so you should turn editor mode off for final testing of your documentation.
Yelp has no refresh button, but the view is automatically refreshed when a document, or any other file in the document directory, changes. This generally works very well, but occasionally can cause Yelp to crash if the document being edited is not valid Mallard. Be sure to use
yelp‑check validate frequently!