diff --git a/extras/test/Makefile b/extras/test/Makefile
index 8515d2c..9d6aa4d 100644
--- a/extras/test/Makefile
+++ b/extras/test/Makefile
@@ -17,7 +17,7 @@
 # You should have received a copy of the GNU General Public License
 # along with this program.  If not, see http://www.gnu.org/licenses/ .
 
-SHELL := /usr/bin/zsh
+SHELL := $(shell which zsh)
 SHELL_PATH ?= $(SHELL)
 SHELL_PATH_SQ = $(subst ','\'',$(SHELL_PATH))
 RM ?= rm -f
diff --git a/extras/test/aggregate-results b/extras/test/aggregate-results
index 958cbea..0666ffa 100644
--- a/extras/test/aggregate-results
+++ b/extras/test/aggregate-results
@@ -1,4 +1,4 @@
-#!/bin/sh
+#!/usr/bin/env zsh
 #
 # Copyright (c) 2008-2012 Git project
 #