On Tue, May 31, 2016 at 11:44:13PM -0400, Jeff King wrote:
> # probably not portable; also, possible without sub-program?
> is_exported () {
> export -p | grep "^declare -x $1="
> }
Obviously this should have been "grep -q" (and my test didn't notice
because the variable isn't actually exported!).
But yeah, this is not very portable. Doing:
export AAAA=content
for i in bash dash mksh ksh93
do
printf '%5s ==> ' $i
$i -c 'export -p' | head -1
done
yields:
bash ==> declare -x AAAA="content"
dash ==> export AAAA='content'
mksh ==> export AAAA=content
ksh93 ==> export AAAA=content
which is actually not too hard to pattern-match, but who knows what else
exists. I guess another strategy would be to actually spawn a
sub-process and see if it has the variable set.
I think my code also doesn't handle exported-but-unset variables, though
I'm not sure we really need to care about that in practice.
-Peff
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