On Thu, May 23, 2024 at 06:56:01AM +0800, Dan Jacobson wrote: > It seems these should both make one line "+ a=b c=b" output, > > for s in sh bash > do $s -xc 'a=b c=$a' > done > > I mean they give the same results, but bash splits it into > two lines, so the user reading the bash -x output cannot tell > if one (correct) or two (incorrect) lines were used. > They can tell with sh -x.
Does it actually matter? What makes bash's output "incorrect", exactly? > By the way, I looked up and down the man page, > and wasn't sure if it says one should expect > $c to end up as c= or c=b in fact! I don't know where it's documented, but assignments and expansions are always performed left to right. In your example, a value is assigned to variable a before $a is expanded. > And I'm not sure the man page says to expect two lines or one of -x > output either, when using sh vs. bash. I don't see why it matters. The purpose of the -x output is to show you what the shell is doing, so that you can debug your script. As long as the output is *clear*, it's doing its job. In bash's case, hobbit:~$ bash -xc 'a=b c=$a' + a=b + c=b you can very easily see the order in which the assignments happen, and the values that are assigned.
