Disable colors if not a tty.

git_cl.py

 #!/usr/bin/env python
 # Copyright (c) 2012 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 # Copyright (C) 2008 Evan Martin <martine@danga.com>
 
 """A git-command for integrating reviews on Rietveld."""
 
 import difflib
@@ skipping 1151 matching lines @@
       url = c.GetIssueURL()
       output.put((b, url, Fore.BLUE if url else Fore.WHITE))
 
   tmp = {}
   alignment = max(5, max(len(ShortBranchName(b)) for b in branches))
   for branch in sorted(branches):
     while branch not in tmp:
       b, i, color = output.get()
       tmp[b] = (i, color)
     issue, color = tmp.pop(branch)
+    reset = Fore.RESET
+    if not sys.stdout.isatty():
+      color = ''
+      reset = ''
     print '  %*s: %s%s%s' % (
-          alignment, ShortBranchName(branch), color, issue, Fore.RESET)
+          alignment, ShortBranchName(branch), color, issue, reset)
 
   cl = Changelist()
   print
   print 'Current branch:',
   if not cl.GetIssue():
     print 'no issue assigned.'
     return 0
   print cl.GetBranch()
   print 'Issue number: %s (%s)' % (cl.GetIssue(), cl.GetIssueURL())
   print 'Issue description:'
@@ skipping 1081 matching lines @@
   GenUsage(parser, 'help')
   return CMDhelp(parser, argv)
 
 
 if __name__ == '__main__':
   # These affect sys.stdout so do it outside of main() to simplify mocks in
   # unit testing.
   fix_encoding.fix_encoding()
   colorama.init()
   sys.exit(main(sys.argv[1:]))