Some of the characters you type during incremental search have special effects.
By default, incremental search performs lax space matching:
each space, or sequence of spaces, matches any sequence of one or more
spaces in the text. Hence, ‘foo bar’ matches ‘foo bar’,
‘foo bar’, ‘foo bar’, and so on (but not ‘foobar’).
More precisely, Emacs matches each sequence of space characters in the
search string to a regular expression specified by the variable
search-whitespace-regexp. For example, to make spaces match
sequences of newlines as well as spaces, set it to
To toggle lax space matching, type M-s <SPC>
isearch-toggle-lax-whitespace). To disable this feature
each space in the search string matches exactly one space.
If the search string you entered contains only lower-case letters, the search is case-insensitive; as long as an upper-case letter exists in the search string, the search becomes case-sensitive. If you delete the upper-case character from the search string, it ceases to have this effect. See Search Case.
To toggle whether or not invisible text is searched, type
M-s i (
isearch-toggle-invisible). See Outline Search.
To search for a newline character, type C-j.
To search for non-ASCII characters, use one of the following methods:
insert-charcommand (see Inserting Text).
isearch-toggle-input-method). You can also turn on a non-default input method with C-^ (
isearch-toggle-specified-input-method), which prompts for the name of the input method. When an input method is active during incremental search, the search prompt includes the input method mnemonic, like this:
Typing M-% in incremental search invokes
query-replace-regexp (depending on search mode) with the
current search string used as the string to replace. A negative
prefix argument means to replace backward. See Query Replace.
Typing M-<TAB> in incremental search invokes
isearch-complete, which attempts to complete the search string
using the search ring as a list of completion alternatives.
See Completion. In many operating systems, the M-<TAB>
key sequence is captured by the window manager; you then need to
isearch-complete to another key sequence if you want to
use it (see Rebinding).
When incremental search is active, you can type C-h C-h to
access interactive help options, including a list of special key
bindings. These key bindings are part of the keymap
isearch-mode-map (see Keymaps).