bug#24897: 24.5; doc for `M' in Dired

[Eli Zaretskii]

> Date: Mon, 7 Nov 2016 10:52:13 -0800 (PST)
> From: Drew Adams <drew.adams@oracle.com>
> 
> This: http://emacs.stackexchange.com/q/28504/105, asks how to make files
> read-only using Dired.  Besides using wdired, the obvious answer is to
> use `M'.
> 
> However, in answering that, it becomes clear that the questioner does
> not know the UNIX command `chmod', and might not know about file and
> directory permissions.

Since the original question was about "making the file read-only", I'm
guessing the OP is on Windows, and if that is so, explaining the
Unix-style permission bits won't help a bit.