[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: $${a,b} brace expansion flaw.
From: |
alex xmb sw ratchev |
Subject: |
Re: $${a,b} brace expansion flaw. |
Date: |
Sat, 20 Jan 2024 23:32:01 +0100 |
~ $ a=BaNaNa ; echo ${a,N}
BaNaNa
~ $ a=BaNaNa ; echo ${a,,N}
Banana
i d say that says pattern for , is only-from-beginning
and for ,, its really a 'pattern'
On Sat, Jan 20, 2024, 23:25 Greg Wooledge <greg@wooledge.org> wrote:
> On Sat, Jan 20, 2024 at 08:55:51PM +0100, Paxsali via wrote:
> > echo ${a,b}
> >
> > I have the latest bash reference manual in front of me and I cannot find
> > this form of brace or shell parameter expasion.
>
> ${parameter^pattern}
> ${parameter^^pattern}
> ${parameter,pattern}
> ${parameter,,pattern}
> Case modification. This expansion modifies the case of
> alpha‐
> betic characters in parameter. The pattern is expanded to
> pro‐
> duce a pattern just as in pathname expansion. Each
> character in
> the expanded value of parameter is tested against pattern,
> and,
> if it matches the pattern, its case is converted.
>
> What this expansion would do, therefore, is convert all of the 'b'
> characters in the value of $a to lowercase. Since 'b' is already
> lowercase, it would be a no-op.
>
> Nevertheless, it is valid syntax.
>
> Here's a similar example that actually does something:
>
> unicorn:~$ a=Banana
> unicorn:~$ echo "${a,B}"
> banana
>
>
Message not available
- Message not available
- Re: $${a,b} brace expansion flaw., Paxsali, 2024/01/20
- Re: $${a,b} brace expansion flaw., Kaz Kylheku, 2024/01/20
- Re: $${a,b} brace expansion flaw., Greg Wooledge, 2024/01/20
- Re: $${a,b} brace expansion flaw.,
alex xmb sw ratchev <=
- Re: $${a,b} brace expansion flaw., Greg Wooledge, 2024/01/20
- Re: $${a,b} brace expansion flaw., alex xmb sw ratchev, 2024/01/20
- Re: $${a,b} brace expansion flaw., Dennis Williamson, 2024/01/20
- Re: $${a,b} brace expansion flaw., alex xmb sw ratchev, 2024/01/21
- Re: $${a,b} brace expansion flaw., Paxsali, 2024/01/21
Re: $${a,b} brace expansion flaw., Chet Ramey, 2024/01/21