diff --git a/Util.py b/Util.py
index 4580644..494c94e 100644
--- a/Util.py
+++ b/Util.py
@@ -49,7 +49,8 @@ def executeCommand( command ):
 	"""
 		executes the shell command such as 'set x=1; myprog $x'
 	"""
-	popen = subprocess.Popen( [ command ], bufsize=1, shell=True, stdout=subprocess.PIPE, stderr=subprocess.PIPE ) # bufsize=1 seems to prevent deadlocks that happen 50% the time
+	popen = subprocess.Popen( [ command ], bufsize=1, shell=True, stdout=subprocess.PIPE, stderr=subprocess.PIPE, executable = '/bin/bash' ) # bufsize=1 seems to prevent deadlocks that happen 50% the time
+	# if we don't specify the optional executable argument, then the default non interactive shell will be used. On debian, the default non-interactive shell is dash, which doesn't understand the keyword 'source' that we use in many places
 	stdout, stderr = popen.communicate()
 	#popen.wait()
 	result = (popen.returncode, stdout, stderr)