Warhammer 40k - Lexicanum:Redirect
A Redirect is a tool that when included on a wiki page automatically sends the reader to another page (or a section thereof).
If you type in "PDF" in the search box or in an article click on the link PDF you will automatically be sent to the page Planetary Defence Forces.
If you have been sent to another page via a Redirect this is displayed under the page name of the page you were sent to (see screenshot: "Redirected from...").
When to use Redirects
The Lexicanum Search is not case sensitive, so it does not matter if you enter for example "pDF", "PdF", "pdf", "PDf" or "PDF", you will always end up on the page PDF (that will then redirect you to the page Planetary Defense Forces of course).
What the Search function can however not do is to automatically correct singular and plural of a search term. Or account for the often quite numerous possible variations of a search term. If somebody were for example looking for information on the (made-up for demonstration purposes) 5th Ganymede Heavy Infantry Regiment he/she could use a variety of search terms such as "5th Ganymede", "Fifth Ganymede", "5th Ganymede Regiment" and a quite large number of other permutations. Another example would be problems with special characters. Example: The novel "Faith & Fire" can also be written as "Faith and Fire".
And since Games Workshop itself does not have stringent naming conventions and the Lexicanum names the corresponding pages exactly as they are written in the sources (see also Naming Conventions) this often leads to somewhat messy situations. Other messy situations arise when the proofreaders at Games Workshop failed to spot spelling mistakes or because there was no standardization for specific names (there are for example several different spelling variants of Isstvan).
Last but not least there are certain terms that many users will consistently (and persistently) misspell.
All these messy situations are resolved by using Redirects (see below on how to include Redirects).
A special case are automatically generated Redirects as a consequence of a page move. When a page is moved to a new name a Redirect is automatically put in place by the Mediawiki system. This can unfortunately sometimes have unintended consequences, for example Double Redirects (see below).
How to use Redirects
To include a Redirect on a page you have to include the code #redirect[[Target pagename]] on the chosen page.
If you want to redirect to the page entitled "Planetary Defense Forces":
#redirect[[Planetary Defence Forces]]
You can also redirect to a specific section of a page instead of to the page as such. For example if you want to redirect from a page to a section of another page (which must exist of course!) you have to include the code #redirect[[Target pagename#Section name]] on the chosen page.
If you want to redirect to the section entitled "System_Defence_Forces" which is a section on the page Planetary Defense Forces:
#redirect[[Planetary Defence Forces#System Defence Forces]]
A Double redirect is a Redirect sending the reader to yet another Redirect. Such constructions should be avoided at all costs and replaced by "normal" Redirects that point directly to the intended target page. The reason for this is simple: the Mediawiki software used by the Lexicanum does not support this. Or in other words: It will not send you further than to the first target pages (which only displays a redirect instruction, see screenshot below).
In this concrete Double redirect example there is a Redirect from Administrator to Administratum that in turn redirects to Adeptus Administratum. A reader entering "Administrator" into the search box or clicking on the link Administrator gets stuck on the page Administratum instead of ending up on the page Adeptus Administratum as intended. Therefore the Redirect on the page Administrator would have to be fixed to point directly to Adeptus Administratum instead of to Administratum as in this example.
An automatically generated list of Double redirects that need fixing is available here. The reasons for the existence of such Double redirects most often are unforeseen consequences of a page move.
More on the Redirect Wikimedia tool can be found here.