On Sun, Jun 28, 2020 at 21:52:23 +0700, Robert Elz wrote: > Date: Fri, 26 Jun 2020 22:05:05 +0000 > From: "Valeriy E. Ushakov" <u...@netbsd.org> > Message-ID: <20200626220505.e9030f...@cvs.netbsd.org> > > | Modified Files: > | src/usr.bin/printf: printf.1 > | > | Log Message: > | Drop redundant quoting in the nested printf example. > > I don't think that is correct, the quotes around 0x0A were obviously > redundant (and changing it to 0x0a doesn't alter that), but those > around the $(printf ...) are not - without those the result from the > command substitution would be subject to field splitting, and if IFS > happens to contain a \ or an octal digit, bad things will happen. > > In general it is never a good idea to omit quotes around sh word > expansions except in the cases where you actually want field splitting > (or pathname expansion, etc) to happen (and sometimes except in the > contexts where those don't occur anyway, like x=$whatever) > > For the example in question, try running it with IFS=1 or IFS=2 > to see what I mean.
Right, but I'd expect people that actually use IFS with octal digits or a backslash to also understand and know how to add necessary quoting in that case. Though perhaps it makes sense to them back for pedagogical purposes. -uwe
