Variable: comint-input-filter
comint-input-filter is a variable defined in comint.el.gz.
Value
comint-nonblank-p
Documentation
Predicate for filtering additions to input history.
Takes one argument, the input. If non-nil, the input may be saved on the input history list. Default is to save anything that isn't all whitespace.
Source Code
;; Defined in /usr/src/emacs/lisp/comint.el.gz
(defvar comint-input-filter #'comint-nonblank-p
"Predicate for filtering additions to input history.
Takes one argument, the input. If non-nil, the input may be saved on the input
history list. Default is to save anything that isn't all whitespace.")