diff --git a/tools/minify-js b/tools/minify-js
index a6a48e1a9f..b61f426385 100755
--- a/tools/minify-js
+++ b/tools/minify-js
@@ -45,11 +45,11 @@ def get_changed_source_files(other_checkout):
     try:
         git_dir = os.path.join(other_checkout, '.git')
         old_commit_sha1 = subprocess.check_output(['git', 'rev-parse', 'HEAD'],
-                                                  env={'GIT_DIR': git_dir})
+                                                  env={'GIT_DIR': git_dir}, universal_newlines=True)
         old_commit_sha1 = old_commit_sha1.rstrip()
 
         git_diff = subprocess.check_output(['git', 'diff', '--name-only',
-                                            old_commit_sha1])
+                                            old_commit_sha1], universal_newlines=True)
     except subprocess.CalledProcessError:
         # If git returned an error, assume we can't reuse any files, and
         # regenerate everything.
@@ -130,5 +130,5 @@ for js_group, filespec in six.iteritems(JS_SPECS):
     js = subprocess.check_output(cmd, shell=True)
 
     # Write out the JS
-    with open(out_file, 'w') as fp:
+    with open(out_file, 'wb') as fp:
         fp.write(js)
diff --git a/tools/post-receive b/tools/post-receive
index 4b754c2717..179ac7cb4d 100755
--- a/tools/post-receive
+++ b/tools/post-receive
@@ -33,7 +33,7 @@ import os
 import sys
 import subprocess
 sys.path.append(os.path.join(os.path.dirname(__file__), '..'))
-from zerver.lib.str_utils import force_str
+from zerver.lib.str_utils import force_str, force_bytes
 from zulip_tools import ENDC, FAIL, subprocess_text_output
 
 def update_deployment(server, refname):
@@ -58,7 +58,7 @@ for ln in sys.stdin:
     if refname in deployments:
         p = subprocess.Popen("/home/zulip/zulip/bots/githook-post-receive",
                              stdin=subprocess.PIPE)
-        p.communicate(input=ln)
+        p.communicate(input=force_bytes(ln))
 
         if deployments[refname]:
             server, branch = deployments[refname]