path: add path.sep to get the path separator.

doc/api/path.markdown

@@ -138,3 +138,19 @@ an empty string.  Examples:
     path.extname('index')
     // returns
     ''
+
+## path.sep
+
+The platform-specific file separator. `'\\'` or `'/'`.
+
+An example on linux:
+
+    'foo/bar/baz'.split(path.sep)
+    // returns
+    ['foo', 'bar', 'baz']
+
+An example on windows:
+
+    'foo\\bar\\baz'.split(path.sep)
+    // returns
+    ['foo', 'bar', 'baz']

lib/path.js

@@ -258,6 +258,7 @@ if (isWindows) {
     return outputParts.join('\\');
   };
 
+  exports.sep = '\\';
 
 } else /* posix */ {
 
@@ -373,6 +374,7 @@ if (isWindows) {
     return outputParts.join('/');
   };
 
+  exports.sep = '/';
 }
 
 

test/simple/test-path.js

@@ -273,3 +273,11 @@ relativeTests.forEach(function(test) {
 });
 assert.equal(failures.length, 0, failures.join(''));
 
+// path.sep tests
+if (isWindows) {
+    // windows
+    assert.equal(path.sep, '\\');
+} else {
+    // posix
+    assert.equal(path.sep, '/');
+}