Question

I want to write a function, similar hexl-find-file, that will open a gzipped file and show the contents in the hexl-mode. How would I do that?

Answer 1

Does this work for you?

(require 'jka-compr)
(defun hexl-find-file ()
  "call find file and then jump into hexl mode"
  (interactive)
  (call-interactively 'find-file)
  (hexl-mode 1))

The 'jka-compr provides the seamless compressed file handling, and the 'hexl-find-file just opens the file and turns on hexl-mode.