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From: Eli Schwartz <eschwartz@archlinux.org>
Newsgroups: gnu.bash.bug
Subject: Re: Command substitution
Date: Tue, 2 Jun 2020 22:02:55 -0400
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On 6/2/20 9:44 PM, Dale R. Worley wrote:
> Naively, I expect that
>=20
>     FOO=3D"$( command2 )"
>     command1 $FOO
>=20
> has the same effect as
>=20
>     command1 $( command2 )
>=20
> and
>=20
>     FOO=3D"$( command2 )"
>     command1 "$FOO"
>=20
> has the same effect as
>=20
>     command1 "$( command2 )"
>=20
> Has anyone pushed the boundaries of this and can tell me whether there
> are gotchas?

What boundaries were you expecting? If this is related to the thread
about the value of $? after command substitution in variable assignment
vs. command arguments... that's already a gotcha according to many
people. Despite being both documented and logical.

Aside for that, obviously in one case you don't have a "FOO" variable in
the shell environment, which does seem like a fairly major difference as
it's a very common pattern for people to reuse the results of command
substitution multiple times.

Perhaps you meant to say "executes the same command process" instead of
"has the same effect"?

--=20
Eli Schwartz
Arch Linux Bug Wrangler and Trusted User


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