How to preview header of files?

[peterb]

I want to see files headers - is this possible? In viewer I see only preview for txt files (and graphics images) but if file is unknown, I see nothing but icon. It should be possible to see header of file somewhere.

[Leo]

Turn off the shell thumbnail and shell icon options in the preview panel's Preferences page and you'll see a hex viewer for unrecognised types.

[peterb]

But it works only for small files. Why not for large ones?

[Leo]

Clear the size here and I think it will work on any size of file:

[peterb]

Great, thank you!