Merge branch 'us/printf-not-echo' into maint

* us/printf-not-echo:
  test-lib.sh: do not "echo" caller-supplied strings
  rebase -i: do not "echo" random user-supplied strings

git-rebase--interactive.sh

@@ -739,7 +739,7 @@ rearrange_squash () {
 					;;
 				esac
 			done
-			echo "$sha1 $action $prefix $rest"
+			printf '%s %s %s %s\n' "$sha1" "$action" "$prefix" "$rest"
 			# if it's a single word, try to resolve to a full sha1 and
 			# emit a second copy. This allows us to match on both message
 			# and on sha1 prefix

t/test-lib.sh

@@ -277,7 +277,7 @@ error "Test script did not set test_description."
 
 if test "$help" = "t"
 then
-	echo "$test_description"
+	printf '%s\n' "$test_description"
 	exit 0
 fi
 
@@ -328,7 +328,7 @@ test_failure_ () {
 	test_failure=$(($test_failure + 1))
 	say_color error "not ok $test_count - $1"
 	shift
-	echo "$@" | sed -e 's/^/#	/'
+	printf '%s\n' "$*" | sed -e 's/^/#	/'
 	test "$immediate" = "" || { GIT_EXIT_OK=t; exit 1; }
 }