Re: [PATCH] git-prompt.sh: shorter equal upstream branch name

From: Junio C Hamano <gitster@pobox.com>
Date: Oct 1, 2014, 17:49 UTC
Message-ID: <xmqqppebptmj.fsf@gitster.dls.corp.google.com>
In-Reply-To: <542B7AF8.6080501@bbn.com>

Richard Hansen <rhansen@bbn.com> writes:

Show 5 quoted lines

>> and there is no hope to "fix" them to stick to
>> the bare-minimum POSIX,
>
> I don't think it'd be hard to convert it to pure POSIX if there was a
> desire to do so.

Not necessarily; if you make it so slow to be usable as a prompt script, that is not a "conversion". Bash-isms in the script is allowed for a reason, unfortunately.

> It would be unwise to go to great lengths to avoid Bashisms, but I think
> it would be smart to use POSIX syntax when it is easy to do so.

In general, I agree with you. People who know only bash tend to overuse bash-isms where they are not necessary, leaving an unreadable mess.

For the specific purpose of Julien's "if the tail part of this string matches the other string, replace that with an equal sign", ${parameter/pattern/string} is a wrong bash-ism to use. But the right solution to count the length of the other string and take a substring of this string from its beginning would require other bash-isms ${#parameter} and ${parameter:offset:length}.

And that's fine.