Redirecting error message from ${parameter:?word}

[Michael Siegel]

Why is it, apparently, not possible to redirect an error message from a
${parameter:?word} expansion to /dev/null within the same shell instance?

Here's some code to demonstrate what I mean:

$ echo "$BASH_VERSION"
4.4.12(1)-release
$ name=Max
$ printf 'Hello, %s.\n' "${name:?}"
Hello, Max.
$ name=
$ printf 'Hello, %s.\n' "${name:?}"
bash: name: parameter null or not set
$ printf 'Hello, %s.\n' "${name:?}" 2>/dev/null
bash: name: parameter null or not set
$ cat test
#!/bin/bash

name="$1"

printf 'Hello, %s.\n' "${name:?}" 2>/dev/null
printf 'Bye\n'
$ ./test Max
Hello, Max.
Bye
$ ./test
./test: line 5: name: parameter null or not set
$ ./test 2>/dev/null
$


--Michael