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25.9 Contents of Directories

A directory is a kind of file that contains other files entered under various names. Directories are a feature of the file system.

Emacs can list the names of the files in a directory as a Lisp list, or display the names in a buffer using the ls shell command. In the latter case, it can optionally display information about each file, depending on the options passed to the ls command.

— Function: directory-files directory &optional full-name match-regexp nosort

This function returns a list of the names of the files in the directory directory. By default, the list is in alphabetical order.

If full-name is non-nil, the function returns the files' absolute file names. Otherwise, it returns the names relative to the specified directory.

If match-regexp is non-nil, this function returns only those file names that contain a match for that regular expression—the other file names are excluded from the list. On case-insensitive filesystems, the regular expression matching is case-insensitive.

If nosort is non-nil, directory-files does not sort the list, so you get the file names in no particular order. Use this if you want the utmost possible speed and don't care what order the files are processed in. If the order of processing is visible to the user, then the user will probably be happier if you do sort the names.

          (directory-files "~lewis")
               ⇒ ("#foo#" "#foo.el#" "." ".."
                   "dired-mods.el" "files.texi"
                   "files.texi.~1~")

An error is signaled if directory is not the name of a directory that can be read.

— Function: directory-files-and-attributes directory &optional full-name match-regexp nosort id-format

This is similar to directory-files in deciding which files to report on and how to report their names. However, instead of returning a list of file names, it returns for each file a list (filename . attributes), where attributes is what file-attributes would return for that file. The optional argument id-format has the same meaning as the corresponding argument to file-attributes (see Definition of file-attributes).

— Function: file-expand-wildcards pattern &optional full

This function expands the wildcard pattern pattern, returning a list of file names that match it.

If pattern is written as an absolute file name, the values are absolute also.

If pattern is written as a relative file name, it is interpreted relative to the current default directory. The file names returned are normally also relative to the current default directory. However, if full is non-nil, they are absolute.

— Function: insert-directory file switches &optional wildcard full-directory-p

This function inserts (in the current buffer) a directory listing for directory file, formatted with ls according to switches. It leaves point after the inserted text. switches may be a string of options, or a list of strings representing individual options.

The argument file may be either a directory name or a file specification including wildcard characters. If wildcard is non-nil, that means treat file as a file specification with wildcards.

If full-directory-p is non-nil, that means the directory listing is expected to show the full contents of a directory. You should specify t when file is a directory and switches do not contain ‘-d’. (The ‘-d’ option to ls says to describe a directory itself as a file, rather than showing its contents.)

On most systems, this function works by running a directory listing program whose name is in the variable insert-directory-program. If wildcard is non-nil, it also runs the shell specified by shell-file-name, to expand the wildcards.

MS-DOS and MS-Windows systems usually lack the standard Unix program ls, so this function emulates the standard Unix program ls with Lisp code.

As a technical detail, when switches contains the long ‘--dired’ option, insert-directory treats it specially, for the sake of dired. However, the normally equivalent short ‘-D’ option is just passed on to insert-directory-program, as any other option.

— Variable: insert-directory-program

This variable's value is the program to run to generate a directory listing for the function insert-directory. It is ignored on systems which generate the listing with Lisp code.