Date: Wed, 22 May 2019 08:43:00 -0400
From: Greg Wooledge <wool...@eeg.ccf.org>
Message-ID: <20190522124300.gz1...@eeg.ccf.org>
| It seems to be unique to bash 5. If it's a bug fix, then I'm not
| understanding the rationale. Backslashes shouldn't be consumed during
| glob expansion.
They should - when a pattern comes from an expansion (be that a
variable expansion, or as here, a command substitution) there needs
to be a way to indicate whether the potential magic chars are in
fact intended as magic chars, or as literals. \ is used for that.
If quoted, everything is literal, and there's no issue, but when
unquoted there needs to be this mechanism. So, I think it was a
bug fix (I recently made very similar fixes to the NetBSD shell).
Uses of this kind of thing are obscure, but they exist.
Here, the $ isn't magic to pathname expansion (glob is not a RE)
so the \ doesn't do anything useful, but consider
ls $( printf %s '\**.c' )
what that should do is list all files that end in .c and start
with an asterisk (star). There the first '*' is to be treated
literally, and the 2nd is the "match anything" metc char. Only
the presence of the \ can distinguish those two cases. (Well, here
one could make the pattern be [*]*.c but that isn't always easy, or
even possible).
kre
