From: Junio C Hamano <gitster@pobox.com>
Date: Wed, 30 Oct 2013 19:30:22 GMT
Subject: Re: [PATCH] Change sed i\ usage to something Solaris' sed can handle
Message-ID: <xmqqeh72blpt.fsf@gitster.dls.corp.google.com>
In-Reply-To: <CAP30j15+E4cz_kwJwaSH7-3agwC5J3jGNfaixSUg2=8xAzZoQg@mail.gmail.com>

Ben Walton <bdwalton@gmail.com> writes:

> On Mon, Oct 28, 2013 at 5:39 PM, Andreas Schwab <schwab@linux-m68k.org> wrote:
>> Ben Walton <bdwalton@gmail.com> writes:
>>
>>> diff --git a/t/t4015-diff-whitespace.sh b/t/t4015-diff-whitespace.sh
>>> index 3fb4b97..0126154 100755
>>> --- a/t/t4015-diff-whitespace.sh
>>> +++ b/t/t4015-diff-whitespace.sh
>>> @@ -145,7 +145,8 @@ test_expect_success 'another test, with --ignore-space-at-eol' 'test_cmp expect
>>>  test_expect_success 'ignore-blank-lines: only new lines' '
>>>       test_seq 5 >x &&
>>>       git update-index x &&
>>> -     test_seq 5 | sed "/3/i \\
>>> +     test_seq 5 | sed "/3/i\\
>>> +\
>>>  " >x &&
>>
>> Why do you need the \<nl>?  Since it is inside double quotes the shell
>> will remove it during expansion.
>
> It's an escape. Without it, sed throws:
>
> sed: -e expression #1, char 5: expected \ after `a', `c' or `i'

I think Andreas means the "feed blank line" part, i.e.

>> +     test_seq 5 | sed "/3/i\\
>> +\
>>  " >x &&

should be the same as

>> +     test_seq 5 | sed "/3/i\\
>>  " >x &&

because the lone \<nl> will be eaten and will not be seen by sed.

Do you see different results on Solaris between the following two?

	$ echo "/3/i\\
	\
	" | od
	$ echo "/3/i\\
        " | od