diff --git a/mapper.py b/mapper.py
new file mode 100755
index 0000000..c35760c
--- /dev/null
+++ b/mapper.py
@@ -0,0 +1,88 @@
+#!/usr/bin/env python2.6
+
+"""
+srcer (a.k.a. Mapper)
+
+srcer is a command-line wrapper for svn. If you've ever found yourself typing
+long svn URL's to perform server-side operations, you can use srcer to simplify
+your life.
+
+srcer maps kewords to SVN urls, so that instead of typing:
+  $ svn lock svn://svn.chromium.org/chrome/trunk/src/chrome/app/nibs/Preferences.xib
+You can type:
+  $ srcer lock //chrome/chrome/app/nibs/Preferences.xib
+
+To add a keyword, type:
+  $ srcer -add chrome svn://svn.chromium.org/chrome/trunk/src
+To remove:
+  $ srcer -rm chrome
+To list:
+  $ srcer -ls
+
+It's that simple.
+"""
+
+import json
+import os
+import re
+import sys
+
+MAP_PATH = os.path.expanduser("~/.src_mapper")
+
+def ReplaceArgs(name_map, args):
+  """Iterates over the name map and replaces any keywords."""
+  for name in name_map:
+    args = map(lambda a: re.sub(r'^//' + name + '(/|$)', name_map[name] + '/', a), args)
+  return args
+
+# srcer always takes at least 2 args.
+if len(sys.argv) < 2:
+  print "srcer -ls, -add name url, -rm name, svn_command //keyword/url"
+  sys.exit()
+
+# Try loading the map into memory.
+if os.path.exists(MAP_PATH):
+  map_fp = open(MAP_PATH, 'r')
+  MAP = json.load(map_fp)
+  map_fp.close()
+else:
+  MAP = {}
+
+# srcer -add name url
+if sys.argv[1] == "-add":
+  if len(sys.argv) != 4:
+    print "add <name> <url>"
+    sys.exit(1)
+  MAP[sys.argv[2]] = sys.argv[3]
+
+  map_fp = open(MAP_PATH, 'w')
+  json.dump(MAP, map_fp, indent=2)
+  map_fp.close()
+
+# srcer -rm name
+elif sys.argv[1] == "-rm":
+  if len(sys.argv) != 3:
+    print "rm <name>"
+    sys.exit(1)
+  del MAP[sys.argv[2]]
+
+  map_fp = open(MAP_PATH, 'w')
+  json.dump(MAP, map_fp, indent=2)
+  map_fp.close()
+
+# srcer -ls
+elif sys.argv[1] == "-ls":
+  max_len = 0
+  for name in MAP:
+    if len(name) > max_len:
+      max_len = len(name)
+
+  print 'SOURCE MAPPINGS:'
+  for name in MAP:
+    print '  ' + name.rjust(max_len) + ' : ' + MAP[name]
+
+# Execute command
+else:
+  args = ['svn']
+  args.extend(ReplaceArgs(MAP, sys.argv[1:]))
+  os.execvp('svn', args)
\ No newline at end of file