Variable: dired-compress-files-alist
dired-compress-files-alist is a variable defined in dired-aux.el.gz.
Value
(("\\.tar\\.gz\\'" . "tar -cf - %i | gzip -c9 > %o")
("\\.tar\\.bz2\\'" . "tar -cf - %i | bzip2 -c9 > %o")
("\\.tar\\.xz\\'" . "tar -cf - %i | xz -c9 > %o")
("\\.tar\\.zst\\'" . "tar -cf - %i | zstd -19 -o %o")
("\\.tar\\.lz\\'" . "tar -cf - %i | lzip -c9 > %o")
("\\.tar\\.lzo\\'" . "tar -cf - %i | lzop -c9 > %o")
("\\.zip\\'" . "zip %o -r --filesync %i")
("\\.pax\\'" . "pax -wf %o %i"))
Documentation
Controls the compression shell command for dired-do-compress-to.
Each element is (REGEXP . CMD), where REGEXP is the name of the archive to which you want to compress, and CMD is the corresponding command.
Within CMD, %i denotes the input file(s), and %o denotes the output file. %i path(s) are relative, while %o is absolute.
Probably introduced at or before Emacs version 25.1.
Source Code
;; Defined in /usr/src/emacs/lisp/dired-aux.el.gz
(defvar dired-compress-files-alist
'(("\\.tar\\.gz\\'" . "tar -cf - %i | gzip -c9 > %o")
("\\.tar\\.bz2\\'" . "tar -cf - %i | bzip2 -c9 > %o")
("\\.tar\\.xz\\'" . "tar -cf - %i | xz -c9 > %o")
("\\.tar\\.zst\\'" . "tar -cf - %i | zstd -19 -o %o")
("\\.tar\\.lz\\'" . "tar -cf - %i | lzip -c9 > %o")
("\\.tar\\.lzo\\'" . "tar -cf - %i | lzop -c9 > %o")
("\\.zip\\'" . "zip %o -r --filesync %i")
("\\.pax\\'" . "pax -wf %o %i"))
"Controls the compression shell command for `dired-do-compress-to'.
Each element is (REGEXP . CMD), where REGEXP is the name of the
archive to which you want to compress, and CMD is the
corresponding command.
Within CMD, %i denotes the input file(s), and %o denotes the
output file. %i path(s) are relative, while %o is absolute.")