Re: [PATCH] Remove "bashism" from contrib/thunderbird-patch-inline/appp.sh

From: Junio C Hamano <gitster@pobox.com>
Date: Mar 29, 2011, 07:09 UTC
Message-ID: <7vei5qtnc5.fsf@alter.siamese.dyndns.org>
In-Reply-To: <4D9103D3.5010403@zoho.com>

Ángel González <ingenit@zoho.com> writes:

> This is wrong.

Not really.

Show 5 quoted lines

> You are replacing bash with sh:
>> -#!/bin/bash
>> +#!/bin/sh
>
> but the script still uses bash-specific syntax (aka. bashishms):

Do you mean some of the parts you quoted are bashism?

>>  PATCH=$(zenity --file-selection)

Even though ancient shells I grew up with did not have $(), it is a way backticks should have been written by Bourne from day one. Historically, handling nesting and interraction between double-quotes and backticks correctly was a nightmare to get right, and different implementations of shells got them always wrong. If you use $(), the headaches go away.

These days, we don't know of any POSIX shell that is widely used and does not understand $(). As such, the above construct is perfectly safe and even preferred over ``. Welcome to the 21st century ;-)

>>  if [ "$?" != "0" ] ; then

While I personally do not like this style (I am old fashioned) and would probably write:

	if test $? != 0
        then
        	...

or make it even more readable by writing it together with the previous statement, i.e.

	PATCH=$(zenity --file-selection) ||
        ...

myself, it is definitely not bash-ism to use [] for conditionals. Some people seem to find it more readable than traditional "test" (not me).

The only major platform that didn't have a reasonable shell was Solaris, but we already have written its /bin/sh off as broken and unusable, and suggest people to use xpg4 or xpg6 shell (see the Makefile).