from __future__ import print_function

and print errors and warnings to sys.stderr

pavelib/docs.py

+from __future__ import print_function
 import sys
 from paver.easy import *
 
@@ -31,13 +32,21 @@ def doc_path(options, allow_default=True):
     path = DOC_PATHS.get(doc_type)
 
     if doc_type == 'default' and not allow_default:
-        print "You must specify a documentation type using '--type'.  Valid options are: {options}".format(
-            options=valid_doc_types())
+        print(
+            "You must specify a documentation type using '--type'.  "
+            "Valid options are: {options}".format(
+                options=valid_doc_types()
+            )
+        )
         sys.exit(1)
 
     if path is None:
-        print "Invalid documentation type '{doc_type}'.  Valid options are: {options}".format(
-            doc_type=doc_type, options=valid_doc_types())
+        print(
+            "Invalid documentation type '{doc_type}'.  "
+            "Valid options are: {options}".format(
+                doc_type=doc_type, options=valid_doc_types()
+            )
+        )
         sys.exit(1)
 
     else:

pavelib/prereqs.py

@@ -89,7 +89,7 @@ def prereq_cache(cache_name, paths, install_func):
             cache_file.write(new_hash)
 
     else:
-        print '{cache} unchanged, skipping...'.format(cache=cache_name)
+        print('{cache} unchanged, skipping...'.format(cache=cache_name))
 
 
 def install_ruby_prereqs():

pavelib/servers.py

 """
 Run and manage servers for local development.
 """
-
+from __future__ import print_function
+import sys
 import argparse
 from paver.easy import *
 from .utils.cmd import django_cmd
@@ -21,7 +22,7 @@ def run_server(system, settings=None, port=None, skip_assets=False):
     If `skip_assets` is True, skip the asset compilation step.
     """
     if system not in ['lms', 'studio']:
-        print "System must be either lms or studio"
+        print("System must be either lms or studio", file=sys.stderr)
         exit(1)
 
     if not skip_assets:

pavelib/utils/envs.py

 """
 Helper functions for loading environment settings.
 """
+from __future__ import print_function
 import os
 import sys
 import json
@@ -34,7 +35,11 @@ class Env(object):
 
         # If the file does not exist, issue a warning and return an empty dict
         if not os.path.isfile(env_path):
-            print "Warning: could not find environment JSON file at '{path}'".format(path=env_path)
+            print(
+                "Warning: could not find environment JSON file "
+                "at '{path}'".format(path=env_path),
+                file=sys.stderr,
+            )
             return dict()
 
         # Otherwise, load the file as JSON and return the resulting dict
@@ -43,7 +48,11 @@ class Env(object):
                 return json.load(env_file)
 
         except ValueError:
-            print "Error: Could not parse JSON in {path}".format(path=env_path)
+            print(
+                "Error: Could not parse JSON "
+                "in {path}".format(path=env_path),
+                file=sys.stderr,
+            )
             sys.exit(1)
 
     @lazy

pavelib/utils/process.py

 """
 Helper functions for managing processes.
 """
-
+from __future__ import print_function
 import sys
 import os
 import subprocess