The following variables can be used to customize omitting.
If non-nil, “uninteresting” files are not listed.
The default is nil.
Uninteresting files are files whose names match regexp
dired-omit-files, plus files whose names end with extension in
dired-omit-extensions. C-x M-o (dired-omit-mode)
toggles its value, which is buffer-local. Put
(dired-omit-mode 1)
inside your dired-mode-hook to have omitting initially turned on in
every Dired buffer (see Installation). You can then use
C-x M-o to unomit in that buffer.
To enable omitting automatically only in certain directories you can add a directory local setting (see Directory Variables in The GNU Emacs manual) for Dired mode
((dired-mode . ((dired-omit-mode . t))))
to a .dir-locals.el file in that directory. You can use the
command add-dir-local-variable to do this.
This buffer-local variable’s value is a regexp, a string. Files whose
names match this regexp will not be displayed. This only has effect
when dired-omit-mode’s value is t.
The default value omits the special directories . and .. and autosave files (plus other files ending in .) (see Examples of Omitting Various File Types).
If non-nil, this variable’s value is a list of extensions
(strings) to omit from Dired listings. Its format is the same as that
of completion-ignored-extensions. The default value is the
elements of completion-ignored-extensions,
dired-latex-unclean-extensions,
dired-bibtex-unclean-extensions and
dired-texinfo-unclean-extensions.
Default: filesystem
This variable controls whether file-name matching is case-insensitive.
By default, when dired-omit-case-fold is set to filesystem,
dired-omit-mode will match filenames and extensions
case-sensitively on Dired buffers visiting case-sensitive filesystems,
and case-insensitively on case-insensitive filesystems. Set it to
nil to be always case-sensitive, and to t to be always
case-insensitive.
This variable determines the localp argument
dired-omit-expunge passes to dired-get-filename. If it
is no-dir, the default, omitting is much faster, but you can
only match against the non-directory part of the file name. Set it to
nil if you need to match the whole file name or t to
match the file name relative to the buffer’s top-level directory.
Temporary marker used by Dired to implement omitting. Should never be used as marker by the user or other packages. There is one exception to this rule: by adding
(setq dired-mark-keys "\C-o") ;; i.e., the value of dired-omit-marker-char ;; (which is not defined yet)
to your ~/.emacs, you can bind the C-o key to insert a C-o marker, thus causing these files to be omitted in addition to the usually omitted files. Unfortunately the files you omitted manually this way will show up again after reverting the buffer, unlike the others. The default value is C-o.