Variable: eshell-input-filter
eshell-input-filter is a customizable variable defined in
em-hist.el.gz.
Value
eshell-input-filter-default
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.
Probably introduced at or before Emacs version 26.1.
Source Code
;; Defined in /usr/src/emacs/lisp/eshell/em-hist.el.gz
(defcustom eshell-input-filter 'eshell-input-filter-default
"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."
:type '(radio (function-item eshell-input-filter-default)
(function-item eshell-input-filter-initial-space)
(function :tag "Other function"))
:risky t)