In my particular case to improve a site's search-engine rankings, I needed two RewriteMaps: 1. Mapping old, numbered URLs to new ones containing article-titles. 2. Mapping new SEO URLs to the old numbered ones. The current implementation of txt-map requires me to keep two files for this -- with columns swapped between them: RewriteMap old2new txt:old2new.txt RewriteMap new2old txt:new2old.txt I'd like to be able to tell, when defining a txt-map, which column in the specified file to treat as the map's key and which -- as value. Something like: RewriteMap old2new txt:1,2:old2new.txt RewriteMap new2old txt:2,1:old2new.txt The run-time memory requirements would be exactly the same, but the mapping-synchronization issues I am currently facing would disappear -- there will be no need to maintain the separate new2old.txt file. I can also imagine other use-cases, where the same file may be used for other purposes and contain multiple columns -- only two of which would be used for building a particular map. BTW, the idea is based on the GNUPlot's flexibility in this regard. Going further along these lines, being able to specify the column-separator may be useful to some people... I can cook-up a patch, if the idea seems sound to the would-be committer(s).