From: "Lawrence Velázquez" <larryv@zsh.org>
To: zsh-users@zsh.org
Subject: Re: triviality regarding $# counts
Date: Sat, 13 Apr 2024 20:30:16 -0400 [thread overview]
Message-ID: <c03f0402-6df1-4ca5-a32a-3840e1573595@app.fastmail.com> (raw)
In-Reply-To: <CAH+w=7bf07RN+vmzE6cnLLrg4Kh+1ziauxiEzanHHUh5xddMMA@mail.gmail.com>
On Sat, Apr 13, 2024, at 5:01 PM, Bart Schaefer wrote:
> On Sat, Apr 13, 2024 at 1:36 PM Ray Andrews <rayandrews@eastlink.ca> wrote:
>>
>> On 2024-04-13 12:45, Bart Schaefer wrote:
>> > redline () { echo -e "$red$*$nrm" }
>> >
>> So, compared to the previous expansion, how would '$*' expand there?
>
> redline a b c
>
> would mean
>
> echo -e "$red$1 $2 $3$nrm"
>
> One word, with two quoted spaces, instead of three words.
>
>> I'm unclear as to the practical difference.
>
> For "echo" it doesn't matter because echo is also going to paste its
> arguments together, but it might matter to some other command.
A different output method should make this clearer:
% f1() { printf '<%s>' "x$@x"; echo; }
% f2() { printf '<%s>' "x$*x"; echo; }
% f1 a b c
<xa><b><cx>
% f2 a b c
<xa b cx>
The command "printf '<%s>' ..." outputs each argument enclosed in
"<...>" (other than the format string itself). Observe that
double-quoted $@ can expand to multiple words, while double-quoted
$* always expands to one.
This actually makes a difference to nearly every command you might
think of, with "echo" being a rare exception (and even then, only
when the first character of IFS is a space).
% arr=(.zshenv .zprofile .zshrc)
% set -x
% wc -c "$arr[@]"
+zsh:44> wc -c .zshenv .zprofile .zshrc
1063 .zshenv
1023 .zprofile
3807 .zshrc
5893 total
% wc -c "$arr[*]"
+zsh:45> wc -c '.zshenv .zprofile .zshrc'
wc: .zshenv .zprofile .zshrc: open: No such file or directory
--
vq
next prev parent reply other threads:[~2024-04-14 0:33 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-04-11 0:56 Ray Andrews
2024-04-12 4:55 ` Lawrence Velázquez
2024-04-12 14:48 ` Ray Andrews
2024-04-12 19:09 ` Bart Schaefer
2024-04-13 1:13 ` Ray Andrews
2024-04-13 1:33 ` Mark J. Reed
2024-04-13 2:28 ` Ray Andrews
2024-04-13 3:25 ` Lawrence Velázquez
2024-04-13 14:37 ` Ray Andrews
2024-04-13 15:14 ` Ray Andrews
2024-04-13 17:19 ` Mark J. Reed
2024-04-13 17:27 ` Mark J. Reed
2024-04-13 18:08 ` Ray Andrews
2024-04-13 19:45 ` Bart Schaefer
2024-04-13 20:36 ` Ray Andrews
2024-04-13 21:01 ` Bart Schaefer
2024-04-14 0:28 ` Ray Andrews
2024-04-14 0:30 ` Lawrence Velázquez [this message]
2024-04-14 3:26 ` Ray Andrews
2024-04-14 3:49 ` Lawrence Velázquez
2024-04-14 4:57 ` Bart Schaefer
2024-04-14 13:24 ` Ray Andrews
2024-04-14 13:35 ` Roman Perepelitsa
2024-04-14 14:06 ` Ray Andrews
2024-04-14 14:15 ` Roman Perepelitsa
2024-04-14 14:53 ` Ray Andrews
2024-04-14 15:11 ` Mark J. Reed
2024-04-14 16:23 ` Ray Andrews
2024-04-14 14:06 ` Mark J. Reed
2024-04-14 14:47 ` Ray Andrews
2024-04-14 14:59 ` Mark J. Reed
2024-04-14 15:51 ` Bart Schaefer
2024-04-14 17:22 ` Ray Andrews
2024-04-14 17:42 ` Mark J. Reed
2024-04-14 18:24 ` Bart Schaefer
2024-04-14 22:00 ` Ray Andrews
2024-04-13 20:11 ` Mark J. Reed
2024-04-13 20:53 ` Bart Schaefer
2024-04-14 0:19 ` Ray Andrews
2024-04-13 1:35 ` Bart Schaefer
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