On Fri, 20 Oct 2023 09:41:26 +0000 (UTC) Etienne Lorrain via Bug reports for the GNU Bourne Again SHell <bug-bash@gnu.org> wrote:
> Configuration Information [Automatically generated, do not change]: > Machine: x86_64 > OS: linux-gnu > Compiler: gcc > Compilation CFLAGS: -g -O2 -flto=auto -ffat-lto-objects -flto=auto > -ffat-lto-objects -fstack-protector-strong -Wformat -Werror=format-security > -Wall > uname output: Linux etienne-7950x 6.2.0-34-generic #34~22.04.1-Ubuntu SMP > PREEMPT_DYNAMIC Thu Sep 7 13:12:03 UTC 2 x86_64 x86_64 x86_64 GNU/Linux > Machine Type: x86_64-pc-linux-gnu > > Bash Version: 5.1 > Patch Level: 16 > Release Status: release > > Description: > simple unmodified cut&paste of a session: > > etienne@etienne-7950x:~$ /bin/bash --version > GNU bash, version 5.1.16(1)-release (x86_64-pc-linux-gnu) > Copyright (C) 2020 Free Software Foundation, Inc. > License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html> > > This is free software; you are free to change and redistribute it. > There is NO WARRANTY, to the extent permitted by law. > etienne@etienne-7950x:~$ /bin/bash > etienne@etienne-7950x:~$ echo > ${HOME}:/home/${USER} > bash: ${HOME}:/home/${USER}: bad substitution > etienne@etienne-7950x:~$ echo ${HOME} > bash: ${HOME}: bad substitution The above commands are chock full of ZERO-WIDTH SPACE characters, encoded as UTF-8. 00000000 65 63 68 6f 20 24 7b e2 80 8b e2 80 8b e2 80 8b |echo ${.........| 00000010 e2 80 8b e2 80 8b e2 80 8b e2 80 8b 48 4f 4d 45 |............HOME| 00000020 7d e2 80 8b e2 80 8b e2 80 8b e2 80 8b e2 80 8b |}...............| 00000030 e2 80 8b e2 80 8b 0a |.......| 00000037 Bash prints these non-printing characters within the diagnostic message exactly as they are, making the fact harder to diagnose. Nevertheless, it is quite correct in pointing out that it is a bad substitution. -- Kerin Millar
