For quite some time the access to recent files has been put forward in GNOME, it happened even more so in 3.6 with a "Recent Files" view in Files (née Nautilus), that makes use of a new recent files backend in gvfs.
This is all very nice but my daily activities still involve a lot of command line usage, and I didn't find any way to mark as recents the files I receive via mutt, the text files I create in vim, the pictures I resize with ImageMagick, etc. That always bothered me at the moment I wanted to access those files, but then I just copied a copy of the file to a scratch directory I had bookmarked, and went on with my work.
Until yesterday, as I finally decided to fix that, and quickly put together recent, a command line utility that just puts the file it gets as argument in the recent files list. It's very simple, uses GFile and GtkRecentManager, and the code is located there: recent.c. It's so simple I guess many others wrote something similar, but here you have, perhaps it will be useful.