On Wed, May 22, 2019 at 05:25:43PM +0700, Robert Elz wrote:
> Date: Tue, 21 May 2019 22:11:20 +0000
> From: Charles-Henri Gros <charles-henri.g...@synopsys.com>
> Message-ID:
> <b51a83f93b459b479b6c4c3fbfe3f9310156f52...@us01wembx1.internal.synopsys.com>
>
> | The existence or not of the file should not have any effect.
>
> But it does, and is intended to. If the mattern matches a file
> (when patyhname expanded as a result of the unquoted command substitution)
> you get the file name produced. If it does not match a file,
> the pattern is left untouched. That is the way that things are
> supposed to work.
With glob metacharacters, sure. But none of the characters in his
variable are glob metacharacters.
There is definitely something weird happening here.
wooledg:/tmp/x$ echo "$BASH_VERSION"
5.0.3(1)-release
wooledg:/tmp/x$ touch 'a$.class'
wooledg:/tmp/x$ i='a\$.class'; echo {$i} "{$i}"
{a\$.class} {a\$.class}
wooledg:/tmp/x$ i='a\$.class'; echo $i "{$i}"
a$.class {a\$.class}
Other versions of bash, plus ksh and dash, don't behave this way.
wooledg:/tmp/x$ bash-2.05b
wooledg:/tmp/x$ i='a\$.class'; echo $i "{$i}"
a\$.class {a\$.class}
wooledg:/tmp/x$ bash-4.4
wooledg:/tmp/x$ i='a\$.class'; echo $i "{$i}"
a\$.class {a\$.class}
wooledg:/tmp/x$ ksh
$ i='a\$.class'; echo $i "{$i}"
a\$.class {a\$.class}
wooledg:/tmp/x$ dash
$ i='a\$.class'; echo $i "{$i}"
a\$.class {a\$.class}
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.
This is also not limited to $ alone. It happens with letters too.
wooledg:/tmp/x$ touch i
wooledg:/tmp/x$ i='\i' j='\j'
wooledg:/tmp/x$ echo $i $j
i \j
Standard disclaimers apply. Stop using unquoted variables and these
bugs will stop affecting you. Nevertheless, Chet may want to take a
peek.
