Having a file for a particular project, I would like all the nodes in that file to have a tag identifying the project, so that I can later use it to create agenda views for that project only. So far all I've found is #+TAGS: foo bar spam which specifies a hard list of tags offered in tag autocompletion for that file.
Does anyone know of a #+XXX-like instruction to achieve this?
Yes. From the Tag inheritance chapter of the org-mode manual (emphasis mine):
Tags make use of the hierarchical structure of outline trees. If a heading has a certain tag, all subheadings will inherit the tag as well. For example, in the list
* Meeting with the French group :work: ** Summary by Frank :boss:notes: *** TODO Prepare slides for him :action:the final heading will have the tags
:work:,:boss:,:notes:, and:action:even though the final heading is not explicitly marked with those tags. You can also set tags that all entries in a file should inherit just as if these tags were defined in a hypothetical level zero that surrounds the entire file. Use a line like this:#+FILETAGS: :Peter:Boss:Secret:
File specific tags can be specified as:
#+FILETAGS: :tag1:tag2:tag3:
These tags then apply to lower level entries through inheritance.
Okay, I found the answer to the question right after posting it... anyway, here it goes for those who might not know how to do this:
#+FILETAGS: :foo:bar:spam:
Found the info in this very useful page with all the in-buffer settings.
