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From: Peter Stephenson <p.w.stephenson@ntlworld.com>
To: zsh-users@zsh.org
Subject: Re: string overwrites string when echoed
Date: Sun, 10 Sep 2017 19:57:58 +0100	[thread overview]
Message-ID: <20170910195758.13290f1b@ntlworld.com> (raw)
In-Reply-To: <86o9qimn03.fsf@zoho.com>

On Sun, 10 Sep 2017 20:23:08 +0200
Emanuel Berg <moasen@zoho.com> wrote:
> Feel free to elaborate on ${reply%%$'\r'}.
> What does it do? Remove the last char of the
> string if it matches the char given?

%% is a standard pattern match operator (works in most shells) that
removes the longest possible match of the following pattern.  % is
similar but removes the shortest possible match: I used %% because they
do the same thing in this case (it's a single fixed character) and I
happen to know the longest match is generally more efficient to
evaluate.  This is documented in the PARAMETER EXPANSION section of the
zshexpn manual.

$'...' is an increasingly common form of quoting that allows escape
sequences like the print builtin, so $'\r' exands to a carriage return.
This is documented in the section QUOTING in the zshmisc manual page
(except it doesn't say much more than what I did before you have to go
away and read the entry for the print builtin).

pws


  reply	other threads:[~2017-09-10 18:58 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-09-09 12:55 Emanuel Berg
2017-09-09 17:01 ` Bart Schaefer
2017-09-10 16:35   ` Emanuel Berg
2017-09-10 16:59     ` Peter Stephenson
2017-09-10 18:23       ` Emanuel Berg
2017-09-10 18:57         ` Peter Stephenson [this message]
2017-09-10 19:01           ` Emanuel Berg
2017-09-10 21:50     ` Bart Schaefer
2017-09-10 22:11       ` Emanuel Berg

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