patchAvoid unportable nested double- and backquotes in shell scripts.

Some shells parse them wrongly, esp. pdksh. On the other hand, the right-hand side of assignments is not word-split, so they can be used as workarounds.

Signed-off-by: Ralf Wildenhues <Ralf.Wildenhues@gmx.de>
---
 contrib/examples/git-fetch.sh |    2 +-
 t/t9107-git-svn-migrate.sh    |    2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

Ralf Wildenhues wrote:

How does it treat $( ) command substitutions? (We use those more heavily and they are easier on the eyes anyway.)

I thought I remembered portability problems with the

	! a | b

construct but it seems I am wrong; t7810-grep.sh uses that construct without trouble, at least.

* Jonathan Nieder wrote on Sat, Jan 08, 2011 at 05:14:41PM CET:

Better (except for the usual problems when 'case ...)' comes into play). But git makes heavy use of "no quoting needed on RHS of assignment" anyway, so it seems like this would be a good move nonetheless. And the testsuite uses backticks a lot, it seems a move away from that should be done more uniformly?

Anyway, I'll be happy to respin in whatever form is acceptable.

Some non-Posix-conforming shells have problems with that too, e.g., Solaris /bin/sh, but I figured git wouldn't cater to them as I also saw other such uses in the tree.

Cheers, Ralf

Ralf Wildenhues wrote:

No disagreement there.

 $ git grep -c -F -e '`' -- 't/*.sh' | cut -d: -f2 | sum
 65126     1
 $ git grep -c -F -e '$(' -- 't/*.sh' | cut -d: -f2 | sum
 64807     1
 $ git grep -c -F -e '`' -- '*.sh' | cut -d: -f2 | sum
 13350     1
 $ git grep -c -F -e '$(' -- '*.sh' | cut -d: -f2 | sum
 07810     1

Documentation/CodingGuidelines 

 - We prefer $( ... ) for command substitution; unlike ``, it
   properly nests.  It should have been the way Bourne spelled
   it from day one, but unfortunately isn't.

I don't see why. :) In fact, I personally would not be happy at all to see such a high-churn patch as that, while using the $( ... ) form in new code and as part of clarifications to other parts of the same lines would seem to me to be a welcome thing.

Having said all that, I have no strong investment in this. Feel free to do what works best for you.

Thanks, Jonathan

Jonathan Nieder wrote:

sum does something totally different than I expected. With [1] comes the more reasonable

 $ git grep -c -F -e '`' -- 't/*.sh' | cut -d: -f2 | addup
 485
 $ git grep -c -F -e '$(' -- 't/*.sh' | cut -d: -f2 | addup
 2620
 $ git grep -c -F -e '`' -- '*.sh' | cut -d: -f2 | addup
 594
 $ git grep -c -F -e '$(' -- '*.sh' | cut -d: -f2 | addup
 3133

So the code bloat and use of backticks are less dire than I feared.

[1] 
	addup () {
		sum=0
		while read term
		do
			: $((sum = $sum + $term))
		done
		echo $sum
	}

Ralf Wildenhues <Ralf.Wildenhues@gmx.de> writes:

I do not very much like the idea of updating contrib/examples, one of whose purposes is to document the historical implementation, to ship a version that has never been battle tested in the field.

There also seem to be a few more uses of `` (the majority used $() even back then) that are still left behind. To make it more useful to serve as an example (which is the other purpose of contrib/examples), it would make more sense to update them all at once.