fix bsd shell negation

On some shells (notably /bin/sh on FreeBSD 6.1), the
construct

  foo && ! bar | baz

is true if

  foo && baz

whereas for most other shells (such as bash) is true if

  foo && ! baz

We can work around this by specifying

  foo && ! (bar | baz)

which works everywhere.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/git-rebase.sh b/git-rebase.sh
index 9b13b83..fbb0f28 100755
--- a/git-rebase.sh
+++ b/git-rebase.sh
@@ -353,7 +353,7 @@
 mb=$(git merge-base "$onto" "$branch")
 if test "$upstream" = "$onto" && test "$mb" = "$onto" &&
 	# linear history?
-	! git rev-list --parents "$onto".."$branch" | grep " .* " > /dev/null
+	! (git rev-list --parents "$onto".."$branch" | grep " .* ") > /dev/null
 then
 	# Lazily switch to the target branch if needed...
 	test -z "$switch_to" || git checkout "$switch_to"
diff --git a/t/t3400-rebase.sh b/t/t3400-rebase.sh
index 496f4ec..fdad7da 100755
--- a/t/t3400-rebase.sh
+++ b/t/t3400-rebase.sh
@@ -44,13 +44,13 @@
 
 test_expect_success \
     'the rebase operation should not have destroyed author information' \
-    '! git log | grep "Author:" | grep "<>"'
+    '! (git log | grep "Author:" | grep "<>")'
 
 test_expect_success 'rebase after merge master' '
      git reset --hard topic &&
      git merge master &&
      git rebase master &&
-     ! git show | grep "^Merge:"
+     ! (git show | grep "^Merge:")
 '
 
 test_expect_success 'rebase of history with merges is linearized' '
diff --git a/t/t3700-add.sh b/t/t3700-add.sh
index 287e058..68c5dde 100755
--- a/t/t3700-add.sh
+++ b/t/t3700-add.sh
@@ -81,17 +81,17 @@
 
 test_expect_success '.gitignore is honored' '
 	git add . &&
-	! git ls-files | grep "\\.ig"
+	! (git ls-files | grep "\\.ig")
 '
 
 test_expect_success 'error out when attempting to add ignored ones without -f' '
 	! git add a.?? &&
-	! git ls-files | grep "\\.ig"
+	! (git ls-files | grep "\\.ig")
 '
 
 test_expect_success 'error out when attempting to add ignored ones without -f' '
 	! git add d.?? &&
-	! git ls-files | grep "\\.ig"
+	! (git ls-files | grep "\\.ig")
 '
 
 test_expect_success 'add ignored ones with -f' '
diff --git a/t/t5302-pack-index.sh b/t/t5302-pack-index.sh
index b88b5bb..09fd917 100755
--- a/t/t5302-pack-index.sh
+++ b/t/t5302-pack-index.sh
@@ -65,7 +65,7 @@
 
 have_64bits=
 if msg=$(git verify-pack -v "test-3-${pack3}.pack" 2>&1) ||
-	! echo "$msg" | grep "pack too large .* off_t"
+	! (echo "$msg" | grep "pack too large .* off_t")
 then
 	have_64bits=t
 else
diff --git a/t/t7501-commit.sh b/t/t7501-commit.sh
index c0288f3..89710af 100755
--- a/t/t7501-commit.sh
+++ b/t/t7501-commit.sh
@@ -41,7 +41,7 @@
 test_expect_success \
 	"using paths with --interactive" \
 	"echo bong-o-bong >file &&
-	! echo 7 | git-commit -m foo --interactive file"
+	! (echo 7 | git-commit -m foo --interactive file)"
 
 test_expect_success \
 	"using invalid commit with -C" \