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From: Bart Schaefer <schaefer@brasslantern.com>
To: Zsh-Users List <zsh-users@zsh.org>
Subject: Re: virtual files?
Date: Wed, 20 Apr 2016 13:34:46 -0700	[thread overview]
Message-ID: <160420133446.ZM13832@torch.brasslantern.com> (raw)
In-Reply-To: <CAB2RFrTTibd-8FLs5GoGbMiTS2Gk8L8CVq1gC5im_8LmF3F6Zw@mail.gmail.com>

On Apr 19, 11:32pm, Benjamin R. Haskell wrote:
}
} Using the `=()` substitution ZyX mentions:
} 
}   () {
}     local tmp=$1
}     wget -q $link -O $tmp
}     echo -n \$
}     grep \"answer\" $tmp | cut -d \$ -f 2 | cut -d \< -f 1
}   } =(:)
} 
} The '() { ... }' construct is an anonymous function, just for controlling
} the scope of the temporary file, and for passing it in as a positional
} parameter.  It has the disadvantage that it won't remove the tmp file if
} something goes wrong.

In fact the point of using =(:) is that it WILL remove the tmp file if
something goes wrong (unless it's something completely catastrophic like
the shell itself crashing, but in that case an explicit "rm" wouldn't
work either).

Instead of exit traps, you can use "always" blocks:

  () {
    local tmp=$1;
    {
      : do stuff with $tmp
      exit
    } always {
      rm $tmp
    }
  } =(:)


  reply	other threads:[~2016-04-20 20:34 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-04-20  1:00 Emanuel Berg
2016-04-20  1:27 ` Nikolay Aleksandrovich Pavlov (ZyX)
2016-04-20  2:12   ` Emanuel Berg
2016-04-20  2:31     ` Nikolay Aleksandrovich Pavlov (ZyX)
2016-04-20  4:03     ` Bart Schaefer
2016-04-20  6:06       ` Emanuel Berg
2016-04-21 22:14       ` Emanuel Berg
2016-04-22  1:08         ` Bart Schaefer
2016-04-20  3:32 ` Benjamin R. Haskell
2016-04-20 20:34   ` Bart Schaefer [this message]
2016-04-22  5:26     ` Benjamin R. Haskell
2016-04-21  4:12   ` Emanuel Berg
2016-04-21  6:58     ` Bart Schaefer
2016-04-21  8:05       ` Emanuel Berg
2016-04-22  5:55     ` Benjamin R. Haskell

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