On Fri, Jan 10, 2014 at 8:20 PM, Bob Proulx <b...@proulx.com> wrote:
>
> Undocumented behavior. Here is the test case:
>
> mkdir /tmp/testdir
> mkdir /tmp/testdir/"newline
> newline"
>
> find /tmp/testdir -print
> /tmp/testdir
> /tmp/testdir/newline?newline
>
> Note the '?' in the above. No '?' in the below that is redirected.
>
> find /tmp/testdir -print | head
> /tmp/testdir
> /tmp/testdir/newline
> newline
>
> If stdout is a tty then the newline is mapped to '?'. But it isn't
> mapped if the output is redirected to a pipe or a file. This applies
> to the printf %p format too.
Yes. This is deliberate in the sense that the code does this
deliberately. I didn't remember perpetrating this inconsistency, but
the git log clearly shows that it was me in change
296989f629a52e1122af688b9d4ddb90f14914b8:(
> This behavior appears to be undocumented. At least I couldn't find a
> reference to behavior differences based upon the output being a tty or
> not.
The fact that this is undocumented is also somewhat deliberate.
Different parts of GNU find do this in slightly different ways. For
example -ls does something similar, but not in quite the same way.
This is confusing and frustrating. It would be good to harmonise and
formalise this better. This is the reason I have not documented the
existing, suboptimal, situation.
This problem is mentioned obliquely in the Texinfo documentation:
3.2 Print File Information
==========================
[...]
9. The file's name. `-ls' quotes non-printable characters in the
file names using C-like backslash escapes. This may change
soon, as the treatment of unprintable characters is
harmonised for `-ls', `-fls', `-print', `-fprint', `-printf'
and `-fprintf'.
> I looked over
> http://pubs.opengroup.org/onlinepubs/009695399/utilities/find.html
> and couldn't find anything allowing this behavior either.
>
> Did that character mapping sneak in unintentionally?
No. I implemented it myself, I would now say in an unwise way, for
https://savannah.gnu.org/bugs/?13303
I think this functionality should be reworked a bit to make it saner.
Unfortunately I am unlikely to get to this in the near future.
James.
