Re: Global variable modification by nameref chain

[Dan Douglas]

On Sun, Jun 12, 2016 at 8:33 PM, Chet Ramey  wrote:
> 3. Honor the assignment and delete the nameref variable, creating a new
>one, like bash-4.3:
>
> $ ../bash-4.3-patched/bash ./x1
> declare -n a="b"
> declare -n b="a[1]"
> declare -a a='([1]="foo")'
> declare -n b="a[1]"

I kind of like this option because it's consistent with `typeset -n`
meaning "operate directly on the ref variable", and declare together
with assignment meaning "redefine the variable" in most cases. I'm not
so sure a warning is needed since replacing the variable with a new
definition would be the usual thing to do with any other attributes,
and the identifier literals used within one scope should be under
control.

Multi-line, double quoted string triggers history expansion on subsequent single-quoted commands it gets piped to

[Néstor Tejero]

Hello,
This is my system:

$ bash --version
GNU bash, version 4.3.11(1)-release (x86_64-pc-linux-gnu)

$ uname -a
Linux PCNTEJERO 3.19.0-51-generic #58~14.04.1-Ubuntu SMP Fri Feb 26
22:02:58 UTC 2016 x86_64 x86_64 x86_64 GNU/Linux
ntejero@PCNTEJERO: ~
$ cat /etc/*ease
DISTRIB_ID=LinuxMint
DISTRIB_RELEASE=17.3
DISTRIB_CODENAME=rosa
DISTRIB_DESCRIPTION="Linux Mint 17.3 Rosa"
NAME="Ubuntu"
VERSION="14.04.4 LTS, Trusty Tahr"
ID=ubuntu
ID_LIKE=debian
PRETTY_NAME="Ubuntu 14.04.4 LTS"
VERSION_ID="14.04"
HOME_URL="http://www.ubuntu.com/;
SUPPORT_URL="http://help.ubuntu.com/;
BUG_REPORT_URL="http://bugs.launchpad.net/ubuntu/;
cat: /etc/upstream-release: Is a directory

Bash was installed through "apt-get install --only-upgrade bash"

The bug:
When printing a multi-line string and piping to another command that uses
single-quotes, Bash tries to perform history expansion:

echo "9
> 10
> 9
> 11" | awk '!seen[$0]++'
bash: !seen[$0]++': event not found
>

$ echo "9
> 10
> 11" | echo '!a'
bash: !a': event not found
>

Turning history off solves it, but anyway history expansion should not
occur within single-quotes. This does not happen in single lines:

$ printf "23\n24\n25" | echo '!a'
!a



Néstor