---

2.7.1 Header Args

‘org-babel-default-header-args’

System-wide values of header arguments, which defaults to the following value, along with an example of how to modify it in the .emacs file:

((:session . "none")
 (:results . "replace")
 (:exports . "code")
 (:cache   . "no")
 (:noweb   . "no")
 (:hlines  . "no")
 (:tangle  . "no"))

(setq org-babel-default-header-args
    (cons '(:noweb . "yes")
        (assq-delete-all :noweb org-babel-default-header-args)))

Each language can have separate default header arguments by customizing the variable ‘org-babel-default-header-args:<LANG>’, where ‘<LANG>’ is the name of the language.

‘PROPERTY’ keyword

For header arguments applicable to the buffer, use ‘PROPERTY’ keyword (Property) anywhere in the Org file.

#+PROPERTY: header-args:R  :session *R*
#+PROPERTY: header-args    :results silent

‘PROPERTIES’ drawer

Header arguments set through Org’s property drawers apply at the sub-tree level on down. Org ignores ‘org-use-property-inheritance’ setting. They override properties set in ‘org-babel-default-header-args’. Properties can also define language-specific header arguments.

* heading
  :PROPERTIES:
  :header-args:    :cache yes
  :END:

* another heading
  :PROPERTIES:
  :header-args:clojure:    :session *clojure-1*
  :header-args:R:          :session *R*
  :END:

‘HEADER’ keyword

Set header arguments for a specific source code block. Takes precedence over Properties and defaults.

#+HEADER: :var data=2