Fix prompt exporting escaped characters, opt into PS1 mod.

go/env.py

Index: go/env.py
diff --git a/go/env.py b/go/env.py
index 71fe12a6ee399c403aa5934ef245124366a8f57e..c541409f9caa2c5d4b8b19908f82ae2e25226784 100755
--- a/go/env.py
+++ b/go/env.py
@@ -32,7 +32,19 @@ new = bootstrap.prepare_go_environ()
 if len(sys.argv) == 1:
   for key, value in sorted(new.iteritems()):
     if old.get(key) != value:
-      print 'export %s=%s' % (key, pipes.quote(value))
+      # Replace special characters with their escaped form. This will allow them

[mithro, 2016/07/07 02:09:39]

Can you move this into a function?

[dnj (Google), 2016/07/07 03:43:30]

Done.

+      # to be interpreted by the shell using the $'...' notation. We will only
+      # use the $'...' notation if there was an escaped character in the string.
+      orig_value = value
+      for f, r in (
+          ('\n', r'\n'),

[mithro, 2016/07/07 02:09:38]

This is kind of confusing, I think

 ('\n', '\\n') 

Would probably be clearer.

[dnj (Google), 2016/07/07 03:43:30]

Done.

+          ('\b', r'\b'),
+          ('\r', r'\r'),
+          ('\t', r'\t'),
+          ('\v', r'\v')):
+        value = value.replace(f, r)
+      print 'export %s=%s%s' % (key, ('$') if orig_value != value else (''),
+                                pipes.quote(value))
 else:
   exe = sys.argv[1]
   if exe == 'python':