Save the latest version when uploading distribution.

.gitignore

@@ -1,5 +1,6 @@
 .DS_Store
 atom-shell.zip
+version
 build/
 dist/
 node/

script/upload

@@ -4,6 +4,7 @@ import errno
 import glob
 import os
 import subprocess
+import tempfile
 
 
 SOURCE_ROOT = os.path.abspath(os.path.dirname(os.path.dirname(__file__)))
@@ -32,17 +33,9 @@ def upload():
     bucket, access_key, secret_key = s3_config()
     commit = subprocess.check_output(['git', 'rev-parse', 'HEAD']).strip()
 
-    args = [
+    s3put(bucket, access_key, secret_key, 'atom-shell/{0}'.format(commit), glob.glob('atom-shell*.zip'))
-        's3put',
-        '--bucket', bucket,
-        '--access_key', access_key,
-        '--secret_key', secret_key,
-        '--prefix', SOURCE_ROOT,
-        '--key_prefix', 'atom-shell/{0}'.format(commit),
-        '--grant', 'public-read'
-    ] + glob.glob('atom-shell*.zip')
 
-    subprocess.check_call(args)
+    update_version(bucket, access_key, secret_key, commit)
 
 
 def s3_config():
@@ -56,6 +49,29 @@ def s3_config():
     return config
 
 
+def update_version(bucket, access_key, secret_key, commit):
+    version_path = os.path.join(SOURCE_ROOT, 'version')
+    with open(version_path, 'w') as version_file:
+      version_file.write(commit)
+
+    # Upload after file is closed, it's required under Windows.
+    s3put(bucket, access_key, secret_key, 'atom-shell', [ version_path ])
+
+
+def s3put(bucket, access_key, secret_key, key_prefix, files):
+    args = [
+        's3put',
+        '--bucket', bucket,
+        '--access_key', access_key,
+        '--secret_key', secret_key,
+        '--prefix', SOURCE_ROOT,
+        '--key_prefix', key_prefix,
+        '--grant', 'public-read'
+    ] + files
+
+    subprocess.check_call(args)
+
+
 if __name__ == '__main__':
     import sys
     sys.exit(main())