Date: Sat, 4 Oct 2025 13:11:07 +0100 From: Frank Leonhardt <freebsd-doc@fjl.co.uk> To: questions@freebsd.org Subject: Re: [List] Re: [List] Re: Nice easy sed question Message-ID: <38822591-5a17-465d-8ef4-02d70db268c1@fjl.co.uk> In-Reply-To: <20250925130240640304783@bob.proulx.com> References: <c1ba0b3e-2754-4bc7-af0b-b570a7693c7a@fjl.co.uk> <20250911221857100915167@bob.proulx.com> <4c223de1-6ed0-4f56-9b50-6cc1355a9790@fjl.co.uk> <ce6d67d5-83eb-44fb-a8bf-fbc0b00e77b7@qeng-ho.org> <20250912161922207688629@bob.proulx.com> <861po7hao1.fsf@ltc.des.dev> <20250925130240640304783@bob.proulx.com>
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On 25/09/2025 20:04, Bob Proulx wrote: > Dag-Erling Smørgrav wrote: >> Bob Proulx writes: >>> and implements this ksh-ism so strictly speaking that is not portable >>> but it does work. >> Incorrect, dollar-quoted strings are part of POSIX. >> >>> This is what POSIX has to say about it. >>> >>> The '$' character is used to introduce parameter expansion, command >>> substitution, or arithmetic evaluation. If an unquoted '$' is followed >>> by a character that is not one of the following: >> You are looking in the wrong place. See XCU 2.2.4: >> >> https://pubs.opengroup.org/onlinepubs/9799919799/utilities/V3_chap02.html#tag_19_02_04 >> >>> The result of $'...' such as $'\n' is strictly speaking "unspecified" >>> behavior by the standard. >> On the contrary, it is perfectly well-defined. > Ah! I always thought that was in the extensions. I wonder if it was > at one time and then it was promoted? > > In any case it is good to know that it can be counted upon now to > always be a supported feature of a standard shell. > > Thanks for the correction! > > Bob I second Bob! You've linked to a very useful page there. I note it's 2024, so I'd be a bit careful of using all of it but at least I can point to it and say "It's POSIX so it's not my fault" :-) It says ${#parameter} is definitely POSIX, which is another thing I've avoided until now. Regards, Frank.help
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