diff --git a/planet/shell/py.py b/planet/shell/py.py
index f4476fa..77cad57 100644
--- a/planet/shell/py.py
+++ b/planet/shell/py.py
@@ -1,4 +1,5 @@
 from subprocess import Popen, PIPE
+import os
 
 def run(script, doc, output_file=None, options={}):
     """ process an Python script """
@@ -10,7 +11,8 @@ def run(script, doc, output_file=None, options={}):
 
     options = sum([['--'+key, value] for key,value in options.items()], [])
 
-    proc = Popen(['python', script] + options,
+    python = os.environ.get('_', 'python')
+    proc = Popen([python, script] + options,
         stdin=PIPE, stdout=out, stderr=PIPE)
 
     stdout, stderr = proc.communicate(doc)