Re: How to test if a variable is declared?

[David]

On Fri, 13 Mar 2020 at 13:59, Peng Yu <address@hidden> wrote:

> What is the best way
> to test whether a viable is declared?

Here's one way:

$ echo "$BASH_VERSION"
4.4.12(1)-release
$ unset v
$ declare -p v ; echo $?
bash: declare: v: not found
1
$ declare v
$ declare -p v ; echo $?
declare -- v
0
$