From: Roman Perepelitsa <roman.perepelitsa@gmail.com>
To: Anthony Fletcher <anthony@bifb.org>
Cc: Zsh Users <zsh-users@zsh.org>
Subject: Re: autoload variables
Date: Tue, 31 Aug 2021 20:11:43 +0200 [thread overview]
Message-ID: <CAN=4vMrq3aD0LzzuQDhZHrs3NAHDhgE-AupLZqcu7ZCGLX2VzQ@mail.gmail.com> (raw)
In-Reply-To: <CAPT4cGdM8BfZFX6yJknBP0NRZ7_LBn6Z0nursR_JK575EJooAQ@mail.gmail.com>
On Tue, Aug 31, 2021 at 2:11 AM Anthony Fletcher <anthony@bifb.org> wrote:
>
> I think that using a function that caches the value and then invoked via $(upif) is easiest. Something like
>
> upif () { export UPIF; echo ${UPIF:=$(ip r | ....) }}
> tcpdump -i $(upif) .......
Assuming that you don't set UPIF manually anywhere else, this code is
equivalent to this:
upif() { ip r | ....}
tcpdump -i $(upif) .......
That export and conditional assignment don't do anything because they
are within a subshell. Anything you export there gets wiped out
immediately and won't be used the next time you invoke $(upif).
Roman.
next prev parent reply other threads:[~2021-08-31 18:13 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-30 15:22 Anthony Fletcher
2021-08-30 15:41 ` Roman Perepelitsa
2021-08-30 16:40 ` René Neumann
2021-08-30 16:57 ` Anthony Fletcher
2021-08-30 19:30 ` Mikael Magnusson
2021-08-30 21:34 ` René Neumann
2021-08-30 21:46 ` Bart Schaefer
2021-08-31 0:10 ` Anthony Fletcher
2021-08-31 18:11 ` Roman Perepelitsa [this message]
2021-08-31 19:16 ` Bart Schaefer
2021-08-30 16:49 ` Bart Schaefer
2021-08-31 20:37 ` Marc Chantreux
2021-08-31 21:03 ` Roman Perepelitsa
2021-09-01 8:29 ` Marc Chantreux
2021-09-01 9:51 ` Roman Perepelitsa
2021-09-01 10:06 ` Marc Chantreux
2021-09-01 13:52 ` Bart Schaefer
2021-09-02 23:09 ` Anthony Fletcher
2021-09-03 0:07 ` Bart Schaefer
2021-09-03 6:52 ` Marc Chantreux
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