Re: A note on modern git plus ancient meld ("wrong number of arguments")

From: Jonathan Nieder <jrnieder@gmail.com>
Date: Feb 10, 2012, 17:59 UTC
Message-ID: <20120210175915.GB19216@burratino>
In-Reply-To: <CAHGBnuPBDO=tnoDFGOcGz4nZh9O_A803STmj7KALLuhwgf=hCg@mail.gmail.com>

Hi,

Sebastian Schuberth wrote:

> On Fri, Feb 10, 2012 at 09:23, Jonathan Nieder <jrnieder@gmail.com> wrote:

Show 5 quoted lines

>> +       meld_version=${meld_version#GNOME }
>> +       meld_version=${meld_version#* }
>
> Hmm, I might be mistaken, but aren't these string operations
> Bash-only? And AFAIK Git is striving for standard sh compatibility ...

They are widely supported in POSIX-style shells. See [1] and Documentation/CodingGuidelines:

 - We use POSIX compliant parameter substitutions and avoid bashisms;
   namely:

   - We use ${parameter-word} and its [-=?+] siblings, and their
     colon'ed "unset or null" form.

   - We use ${parameter#word} and its [#%] siblings, and their
     doubled "longest matching" form.

A good way to catch these things is to try with dash or posh, which are a little less full-featured than bash and ksh.

Thanks for looking it over. Jonathan

[1] http://pubs.opengroup.org/onlinepubs/9699919799/ Search for "sh -".