Omitting a file means removing it from the directory listing. Omitting is useful for keeping Dired buffers free of “uninteresting” files (for instance, auto-save, auxiliary, backup, and revision control files) so that the user can concentrate on the interesting files. Like hidden files, omitted files are never seen by Dired. Omitting differs from hiding in several respects:
dired-omit-mode) Toggle between displaying and omitting “uninteresting” files.
dired-mark-omitted) Mark “uninteresting” files.
In order to make Dired Omit work you first need to load dired-x.el
dired-load-hook (see Installation) and then evaluate
(dired-omit-mode 1) in some way (see Omitting Variables).