Re: POSIX woes in t7810.87: dash bash or bash dash?

Jeff King [off-list ref] writes:

On Mon, Jun 20, 2011 at 02:46:08PM -0700, Junio C Hamano wrote:

quoted

diff --git a/t/t7810-grep.sh b/t/t7810-grep.sh
index 69bd576..6379ad6 100755
--- a/t/t7810-grep.sh
+++ b/t/t7810-grep.sh

@@ -658,9 +658,9 @@ test_expect_success LIBPCRE 'grep -P -v pattern' '
 '
 
 test_expect_success LIBPCRE 'grep -P -i pattern' '
-	{
-		echo "hello.c:	printf(\"Hello world.\n\");"
-	} >expected &&
+	cat >expected <<-EOF &&
+	hello.c:	printf("Hello world.\n");
+	EOF

Do you need to quote EOF to suppress expansion in the here document?
Both bash and dash seem to pass unknown backslash-escapes like "\n"
through unharmed, but I don't know if that is portable (they do both
munge known escapes like "\\", of course).

I do not think that is strictly necessary, as we are not in the corner of
non-portable echo behaviour anymore, but I guess it wouldn't hurt.

On Mon, Jun 20, 2011 at 04:31:32PM -0700, Junio C Hamano wrote:

quoted

quoted

+	cat >expected <<-EOF &&
+	hello.c:	printf("Hello world.\n");
+	EOF

Do you need to quote EOF to suppress expansion in the here document?
Both bash and dash seem to pass unknown backslash-escapes like "\n"
through unharmed, but I don't know if that is portable (they do both
munge known escapes like "\\", of course).

I do not think that is strictly necessary, as we are not in the corner of
non-portable echo behaviour anymore, but I guess it wouldn't hurt.

I think my brain is fried from using too many almost-shell-compatible
quoting languages. For example, unknown escape sequences in C get their
backslash removed and the sequence used literally (at least by gcc; I
couldn't find anything definite in C99 on this).

But actually, POSIX is quite clear that a backslash before anything
besides:

  $   `   "   \   <newline>

is just a backslash, and gets included literally.

-Peff