+(defvar dired-compress-file-suffixes
+ '(("\\.gz\\'" "" "gunzip")
+ ("\\.tgz\\'" ".tar" "gunzip")
+ ("\\.Z\\'" "" "uncompress")
+ ;; For .z, try gunzip. It might be an old gzip file,
+ ;; or it might be from compact? pack? (which?) but gunzip handles both.
+ ("\\.z\\'" "" "gunzip")
+ ("\\.bz2\\'" "" "bunzip2")
+ ;; This item controls naming for compression.
+ ("\\.tar\\'" ".tgz" nil))
+ "Control changes in file name suffixes for compression and uncompression.
+Each element specifies one transformation rule, and has the form:
+ (REGEXP NEW-SUFFIX PROGRAM)
+The rule applies when the old file name matches REGEXP.
+The new file name is computed by deleting the part that matches REGEXP
+ (as well as anything after that), then adding NEW-SUFFIX in its place.
+If PROGRAM is non-nil, the rule is an uncompression rule,
+and uncompression is done by running PROGRAM.
+Otherwise, the rule is a compression rule, and compression is done with gzip.")
+