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Groups > gnu.bash.bug > #15303

Re: Setting nullglob causes variables containing backslashes to be expanded to an empty string

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2019-08-06 21:28:20 +0100, Stephane Chazelas:
[...]
> That is being discussed on the austingroup mailing list (and has
> been discussed here before as well).
> 
> The idea is that in 5.0, \ became a globbing quoting operator.
> 
> So with nullglob, the \x30 expands to x30 when there's a file
> called x30 in the current directory and nothing if not.
> 
> That is by design and was supported until relatively recently by
> some Austin group people (the guys behind POSIX).
[...]

with the current head of the  devel branch, that behaviour can
be disabled by turning off the posixglob option (I still do hope
that POSIX will give up on this silly idea).

$ a='\x30' ./bash +O posixglob -O nullglob -c 'printf "%s\n" $a'
\x30
$ a='\x30' ./bash -O nullglob -c 'printf "%s\n" $a'

$ a='\x30' ./bash -O nullglob -c 'printf "%s\n" $a'
x30


In any case, yes, do remember to quote your variable expansions
and not use echo for arbitrary data.

-- 
Stephane

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Re: Setting nullglob causes variables containing backslashes to be expanded to an empty string Greg Wooledge <wooledg@eeg.ccf.org> - 2019-08-06 16:00 -0400
  Re: Setting nullglob causes variables containing backslashes to be expanded to an empty string Stephane Chazelas <stephane.chazelas@gmail.com> - 2019-08-06 21:28 +0100
    Re: Setting nullglob causes variables containing backslashes to be expanded to an empty string Stephane Chazelas <stephane.chazelas@gmail.com> - 2019-08-06 21:39 +0100
      Re: Setting nullglob causes variables containing backslashes to be expanded to an empty string Stephane Chazelas <stephane.chazelas@gmail.com> - 2019-08-06 21:42 +0100

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