The #, ~, ., % &, and % d commands flag many files for deletion, based on their file names:
Flag all auto-save files (files whose names start and end with ‘#’) for deletion (see Auto Save).
Flag all backup files (files whose names end with ‘~’) for deletion (see Backup).
Flag excess numeric backup files for deletion. The oldest and newest few backup files of any one file are exempt; the middle ones are flagged.
Flag for deletion all files with certain kinds of names which suggest you could easily create those files again.
Flag for deletion all files whose names match the regular expression regexp.
dired-flag-auto-save-files) flags all files whose
names look like auto-save files—that is, files whose names begin and
end with ‘#’. See Auto Save.
dired-flag-backup-files) flags all files whose names
say they are backup files—that is, files whose names end in
‘~’. See Backup.
dired-clean-directory) flags just some of
the backup files for deletion: all but the oldest few and newest few
backups of any one file. Normally, the number of newest versions kept
for each file is given by the variable
kept-new-versions; that applies only when saving).
The number of oldest versions to keep is given by the variable
Period with a positive numeric argument, as in C-u 3 .,
specifies the number of newest versions to keep, overriding
dired-kept-versions. A negative numeric argument overrides
kept-old-versions, using minus the value of the argument to
specify the number of oldest versions of each file to keep.
% & (
dired-flag-garbage-files) flags files whose names
match the regular expression specified by the variable
dired-garbage-files-regexp. By default, this matches certain
files produced by TeX, ‘.bak’ files, and the ‘.orig’ and
‘.rej’ files produced by
% d flags all files whose names match a specified regular
dired-flag-files-regexp). Only the non-directory
part of the file name is used in matching. You can use ‘^’ and
‘$’ to anchor matches. You can exclude certain subdirectories
from marking by hiding them while you use % d. See Hiding Subdirectories.