Re: [PATCH 4/4] digest: support windows format checksum files

[Eric Blake]

On Wed, Sep 15, 2021 at 01:40:36PM +0100, Pádraig Brady wrote:
> Support checksum files with CRLF line endings,
> which is a common gotcha for using --check on windows,
> or with checksum files generated on windows.
> Note we escape \r here to support the original coreutils format
> (with file name at EOL), and file names with literal
> \r characters as the last character of their name.
> 

> +++ b/doc/coreutils.texi
> @@ -4066,10 +4066,12 @@ Binary mode is indicated with @samp{*}, text mode 
> with @samp{ } (space).
>  Binary mode is the default on systems where it's significant,
>  otherwise text mode is the default.  The @command{cksum} command always
>  uses binary mode and a @samp{ } (space) flag.
> -Without @option{--zero}, if @var{file} contains a backslash or newline,
> -the line is started with a backslash, and each problematic character in
> -the file name is escaped with a backslash, making the output
> -unambiguous even in the presence of arbitrary file names.

Pre-existing, but...

> +
> +Without @option{--zero}, if @var{file} contains a backslash, newline,
> +or carriage return, the line is started with a backslash, and each
> +problematic character in the file name is escaped with a backslash,
> +making the output unambiguous even in the presence of arbitrary file names.

We output backslash-n, not backslash-newline, when escaping newline.
And with the new carriage return escaping, we output backslash-r, not
backslash-CR.  So this sentence is a bit misleading in stating that
the problematic character is escaped with backslash, when in reality
it is replaced by an escape sequence that starts with backslash.

Overall, I like where you're headed with this.

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3266
Virtualization:  qemu.org | libvirt.org