Re: [PATCH] fdtget-runtest.sh: Fix failures when /bin/sh isn't bash

[David Gibson <david-xT8FGy+AXnRB3Ne2BGzF6laj5H9X9Tb+@public.gmane.org>]

On Tue, Nov 06, 2012 at 10:27:46AM -0700, Stephen Warren wrote:
> On 11/06/2012 12:26 AM, David Gibson wrote:
> > On Mon, Nov 05, 2012 at 10:39:30AM -0700, Stephen Warren wrote:
> >> On 11/02/2012 02:26 PM, Mike Frysinger wrote:
> >>> On Tuesday 20 March 2012 22:23:46 Stephen Warren wrote:
> >>>> On Ubuntu, /bin/sh is dash (at least by default), and dash's echo
> >>>> doesn't accept the -e option. This means that fdtget-runtest.sh's
> >>>> EXPECT file will contain "-e foo" rather than just "foo", which
> >>>> causes a test failure.
> >>>>
> >>>> To work around this, run /bin/echo instead of (builtin) echo,
> >>>> which has more chance of supporting the -e option.
> >>>>
> >>>> Another possible fix is to change all the #! lines to /bin/bash
> >>>> rather than /bin/sh, and change run_tests.sh to invoke
> >>>> sub-scripts using $SHELL instead of just "sh". However, that
> >>>> would require bash specifically, which may not be desirable.
> >>>>
> >>>> --- a/tests/fdtget-runtest.sh +++ b/tests/fdtget-runtest.sh
> >>>>
> >>>> -echo -e $expect >$EXPECT +/bin/echo -e $expect >$EXPECT
> >>>
> >>> the better fix is to use printf and %b: printf '%b\n' "$expect" >
> >>> $EXPECT
> >>
> >> What is the relative availability (e.g. on anything other than a
> >> modern Linux distro) of a printf binary vs. a /bin/echo binary that
> >> supports -e? I certainly heard about /bin/echo -e long before I knew
> >> about /usr/bin/printf, although it's quite possible that has no
> >> correlation with where /usr/bin/printf is actually installed.
> > 
> > That's the crux of the matter, really.  I just had a look on a FreeBSD
> > box I have access to and /bin/echo does *not* support -e, but there is
> > a printf(1).  So the /bin/echo -e approach is definitely no good,
> > printf might be but I don't know how widespread it is.
> 
> Out of curiosity, does FreeBSD's sh's built-in echo accept the -e
> option? In other words, did the switch to /bin/echo break anything
> there?

Yes it does, so yes it does.

> For reference, I just booted my ancient Red Hat 7.3 virtual machine, and
> it has printf, so I guess it's fairly widely available.
> 
> A quick search yields the following:
> 
> http://old.nabble.com/Re%3A-portability-of-%27printf%27-command-td28144087.html
> 
> which comes to the conclusion that printf is widely available enough to
> be OK.
> 
> Oh, and if you find "Portable Shell Scripting" by Peter Seebach on
> Google Books or in print, page 18 discusses the portability of printf,
> and concludes that it's almost pervasive.

Ok, good to hear.

-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson