Re: [BUGS] test failure in t4014-format-patch.sh with master

On 2008.04.17 08:44:07 -0700, Linus Torvalds wrote:

On Thu, 17 Apr 2008, Björn Steinbrink wrote:

quoted

Debian has its own dash which is supposed to be a lightweight
alternative to bash and "for checking POSIX compliance of scripts"
(quote from the packages description). I don't happen to know off-hand
whether POSIX says that echo should default to -e, but dash seems to do
that:

$ dash
$ a="hello\nhi"
$ echo $a
hello
hi

Ahh. So that "echo" should just be replaced with a 'printf "%s\n"' 
instead? 

We have a _lot_ of "echo"s though. I suspect the only ones we'd ever catch 
are the ones explicitly tested for. I suspect that the dash echo is just 
broken.

Wow, seems that "echo" in itself is "broken". According to POSIX[1]
backslashes induce implementation defined behaviour, and there seem to
be two historic versions of echo, one that knows about -n and one that
interprets escape sequences. So echo is totally non-portable unless you
avoid -n as well as backslashes. Ouch.

The POSIX docs, as well as random Google results, indeed recommend to
use printf instead. But that switch seems painful as well...

Björn

[1] http://www.opengroup.org/onlinepubs/009695399/utilities/echo.html