On Tue, 27 Jun 2023 18:37:37 +0200
Fabien Orjollet <of1+bugb...@disroot.org> wrote:
> I'm far from having the skills of the people here. However, I found the
> problem interesting. I think I've come up with a reasonable solution
> (you tell me). Although it's not as short as Kerin Millar's, I think it
> offers some improvements. I hope there are no particular weaknesses.
> If it's of any use to anyone.
>
>
> declare-P() {
> local curVar
> declare -a curVars
>
> readarray -t curVars <<<"$1"
> curVars=( "${curVars[@]%%=*}" )
> curVars=( "${curVars[@]##* }" )
>
> for curVar in "${curVars[@]}"; do
> ### unfortunately, we cannot use [[ -v "$curVar" ]]
> [[ "${curVar//[a-zA-Z0-9_]}" || \
> "${curVar:0:1}" == [0-9] || \
> ! "$curVar" =~ $2 ]] || printf '%s\n' "$curVar"
> done
> }
>
> declare-P "$(declare -p)"
> echo "##################"
> declare-P "$(declare -p)" "TERM"
> echo "##################"
> declare-P "$(declare -p)" "^BASH|^SHELL"
>
It doesn't work at all for >=5.2. The reason for this is interesting and I may
make a separate post about it.
Prior to 5.2, it can easily be tricked into printing names that do not exist.
$ VAR=$'\nNONEXISTENT=' ./declare-P | grep ^NONEXISTENT
NONEXISTENT
All of this lends further credence to Eli's post. Parsing declare -F is a minor
nuisance, whereas parsing declare -p is broken by design. While the format of
declare -p improved for 5.2, there is no guarantee of forward-compatibility.
--
Kerin Millar
