How to let bash subshell to inherit parent’s set options?

September 22, 2023 by Tarik

export SHELLOPTS

for example:

echo date > b
chmod +x b

without the export, we only see the commands in ./a when it calls ./b:

$ echo ./b > a
$ bash -xv a

./a
+ ./b
Sun Dec 29 21:34:14 EST 2013

but if we export SHELLOPTS, we see the commands in ./a and ./b

$ echo "export SHELLOPTS; ./b" > a
$ bash -xv a

./a
+ ./b  date
++ date   
Sun Dec 29 21:34:36 EST 2013