Re: [PATCH] Fix '\%o' for printf from coreutils

From: Jeff King <peff@peff.net>
Date: Oct 31, 2013, 16:49 UTC
Message-ID: <20131031164920.GA18036@sigill.intra.peff.net>
In-Reply-To: <20131031115131.GA28379@camk.edu.pl>

On Thu, Oct 31, 2013 at 12:51:32PM +0100, Kacper Kornet wrote:

Show 9 quoted lines

> The printf utility provided by coreutils when interpreting '\%o' format
> does not recognize %o as formatting directive. For example
> printf '\%o 0 returns \%o and warning: ignoring excess arguments,
> starting with ‘0’, which results in failed tests in
> t5309-pack-delta-cycles.sh. In most shells the test ends with success as
> the printf is a builtin utility.
> 
> Fix it by using '\\%o' which is interpreted consistently in all versions
> of printf.

Thanks, this makes sense. POSIX says:

     [description of \n, \r, etc...]
     The interpretation of a backslash followed by any other
     sequence of characters is unspecified.

so we were wrong to rely on an unknown backslash-escape being left alone. A quick grep seems indicate that this is the only spot with the problem.

-Peff