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Date: Sat, 30 Aug 2014 12:11:46 +0200
Message-ID: <CAHYJk3QZ9H_4Uup=C_u1O8iBqGTC3qcWo5FvPggGU=A0xRG9-w@mail.gmail.com>
Subject: Re: cat as a builtin command
From: Mikael Magnusson <mikachu@gmail.com>
To: Zsh Users <zsh-users@zsh.org>
Content-Type: text/plain; charset=UTF-8

On 29 August 2014 15:03, Peter Stephenson <p.stephenson@samsung.com> wrote:
> On Fri, 29 Aug 2014 09:40:29 +0800
> Izumi Natsuka <izumi.natsuka@hotmail.com> wrote:
>> Hello, I'm going to write a shell function that provides a basic
>> functionality(print the content of a file or stdin) of cat[0], in
>> order to avoid forking too many process when I call it in a
>> loop[1]. And I have put the following in my zshrc:
>
> If it's just printing the contents of a file, investigate zsh/mapfile.
> This turns off multibyte mode to make it easier to do binary files ---
> there should be no disadvantage here as you just want a byte stream.
>
>
> mycat() {
>   emulate -L zsh
>   unsetopt multibyte
>   zmodload zsh/mapfile
>   print -r $mapfile[$1]
> }
>
>
> This only works for files in the file system, not file descriptors,
> pipes etc.  For those you can often optimise out the cat entirely.
>
> pws

mycat() { for i { print -r - "$(< $i)" } }
(also only works for files)

-- 
Mikael Magnusson