diff two files in two windows

Question

After creating a split window and using dired in each, how do I run diff to compare two files?

I have looked but haven't found any clear explanation.

Answer 1

Not clear what you're asking.

But in Dired, provided you've loaded (e.g. required) library dired-aux.el, you can use = (or menu Immediate > Diff), which runs command dired-diff, to diff the file listed on the current line against another file, for which you're prompted.

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If you use library Dired+ (dired+.el), then = runs command diredp-ediff instead:

= runs the command diredp-ediff (found in dired-mode-map), which is an interactive compiled Lisp function in dired+.el.

It is bound to =, menu-bar immediate ediff.

(diredp-ediff FILE2)

Compare file at cursor with file FILE2 using ediff.

FILE2 defaults to the file at the cursor as well. If you enter just a directory name for FILE2, then the file at the cursor is compared with a file of the same name in that directory. FILE2 is the second file given to ediff; the file at the cursor is the first.

Try to guess a useful default value for FILE2, as follows:

• If the mark is active, use the file at mark.

• Else if the file at cursor is a autosave file or a backup file, use the corresponding base file.

• Else if there is any backup file for the file at point, use the newest backup file for it.

• Else use the file at point.

Answer 2

I find using ediff the easiest way to compare 2 files