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8.5 Minibuffer History

Every argument that you enter with the minibuffer is saved in a minibuffer history list so you can easily use it again later. You can use the following arguments to quickly fetch an earlier argument into the minibuffer:

M-p
<Up>
Move to the previous item in the minibuffer history, an earlier argument (previous-history-element).
M-n
<Down>
Move to the next item in the minibuffer history (next-history-element).
M-r regexp <RET>
Move to an earlier item in the minibuffer history that matches regexp (previous-matching-history-element).
M-s regexp <RET>
Move to a later item in the minibuffer history that matches regexp (next-matching-history-element).

While in the minibuffer, M-p or <Up> (previous-history-element) moves through the minibuffer history list, one item at a time. Each M-p fetches an earlier item from the history list into the minibuffer, replacing its existing contents. Typing M-n or <Down> (next-history-element) moves through the minibuffer history list in the opposite direction, fetching later entries into the minibuffer.

If you type M-n in the minibuffer when there are no later entries in the minibuffer history (e.g., if you haven't previously typed M-p), Emacs tries fetching from a list of default arguments: values that you are likely to enter. You can think of this as moving through the “future history” list.

If you edit the text inserted by the M-p or <M-n> minibuffer history commands, this does not change its entry in the history list. However, the edited argument does go at the end of the history list when you submit it.

You can use M-r (previous-matching-history-element) to search through older elements in the history list, and M-s (next-matching-history-element) to search through newer entries. Each of these commands asks for a regular expression as an argument, and fetches the first matching entry into the minibuffer. See Regexps, for an explanation of regular expressions. A numeric prefix argument n means to fetch the nth matching entry. These commands are unusual, in that they use the minibuffer to read the regular expression argument, even though they are invoked from the minibuffer. An upper-case letter in the regular expression makes the search case-sensitive (see Search Case).

You can also search through the history using an incremental search. See Isearch Minibuffer.

Emacs keeps separate history lists for several different kinds of arguments. For example, there is a list for file names, used by all the commands that read file names. Other history lists include buffer names, command names (used by M-x), and command arguments (used by commands like query-replace).

The variable history-length specifies the maximum length of a minibuffer history list; adding a new element deletes the oldest element if the list gets too long. If the value is t, there is no maximum length.

The variable history-delete-duplicates specifies whether to delete duplicates in history. If it is non-nil, adding a new element deletes from the list all other elements that are equal to it. The default is nil.