M.11 Accessing Compressed Files

Emacs comes with a library that can automatically uncompress compressed files when you visit them, and automatically recompress them if you alter them and save them. To enable this feature, type the command M-x auto-compression-mode. You can enable it permanently by customizing the option auto-compression-mode.

When automatic compression (which implies automatic uncompression as well) is enabled, Emacs recognizes compressed files by their file names. File names ending in `.gz' indicate a file compressed with gzip. Other endings indicate other compression programs.

Automatic uncompression and compression apply to all the operations in which Emacs uses the contents of a file. This includes visiting it, saving it, inserting its contents into a buffer, loading it, and byte compiling it.