This chapter describes the Emacs Lisp functions and variables to find, create, view, save, and otherwise work with files and directories. A few other file-related functions are described in Buffers, and those related to backups and auto-saving are described in Backups and Auto-Saving.
Many of the file functions take one or more arguments that are file
names. A file name is a string. Most of these functions expand file
name arguments using the function
expand-file-name, so that
~ is handled correctly, as are relative file names (including
../ and the empty string). See File Name Expansion.
In addition, certain magic file names are handled specially. For example, when a remote file name is specified, Emacs accesses the file over the network via an appropriate protocol. See Remote Files in The GNU Emacs Manual. This handling is done at a very low level, so you may assume that all the functions described in this chapter accept magic file names as file name arguments, except where noted. See Magic File Names, for details.
When file I/O functions signal Lisp errors, they usually use the
file-error (see Handling Errors). The error
message is in most cases obtained from the operating system, according
system-messages-locale, and decoded using coding system
locale-coding-system (see Locales).
|• Visiting Files:||Reading files into Emacs buffers for editing.|
|• Saving Buffers:||Writing changed buffers back into files.|
|• Reading from Files:||Reading files into buffers without visiting.|
|• Writing to Files:||Writing new files from parts of buffers.|
|• File Locks:||Locking and unlocking files, to prevent simultaneous editing by two people.|
|• Information about Files:||Testing existence, accessibility, size of files.|
|• Changing Files:||Renaming files, changing permissions, etc.|
|• Files and Storage:||Surviving power and media failures|
|• File Names:||Decomposing and expanding file names.|
|• Contents of Directories:||Getting a list of the files in a directory.|
|• Create/Delete Dirs:||Creating and Deleting Directories.|
|• Magic File Names:||Special handling for certain file names.|
|• Format Conversion:||Conversion to and from various file formats.|