diff --git a/client.py b/client.py
index 214b038ffa71..60729dcd40a7 100755
--- a/client.py
+++ b/client.py
@@ -3,6 +3,7 @@
 # License, v. 2.0. If a copy of the MPL was not distributed with this
 # file, You can obtain one at http://mozilla.org/MPL/2.0/.
 
+from __future__ import absolute_import, print_function
 
 LIBFFI_DIRS = (('js/ctypes/libffi', 'libffi'),)
 HG_EXCLUSIONS = ['.hg', '.hgignore', '.hgtags']
@@ -22,7 +23,7 @@ if topsrcdir == '':
     topsrcdir = '.'
 
 def check_call_noisy(cmd, *args, **kwargs):
-    print "Executing command:", cmd
+    print("Executing command:", cmd)
     check_call(cmd, *args, **kwargs)
 
 def do_hg_pull(dir, repository, hg):
@@ -67,22 +68,22 @@ def do_cvs_export(modules, tag, cvsroot, cvs):
         cvs_module = module_tuple[1]
         fullpath = os.path.join(topsrcdir, module)
         if os.path.exists(fullpath):
-            print "Removing '%s'" % fullpath
+            print("Removing '%s'" % fullpath)
             shutil.rmtree(fullpath)
 
         (parent, leaf) = os.path.split(module)
-        print "CVS export begin: " + datetime.datetime.utcnow().strftime("%Y-%m-%d %H:%M:%S UTC")
+        print("CVS export begin: " + datetime.datetime.utcnow().strftime("%Y-%m-%d %H:%M:%S UTC"))
         check_call_noisy([cvs, '-d', cvsroot,
                           'export', '-r', tag, '-d', leaf, cvs_module],
                          cwd=os.path.join(topsrcdir, parent))
-        print "CVS export end: " + datetime.datetime.utcnow().strftime("%Y-%m-%d %H:%M:%S UTC")
+        print("CVS export end: " + datetime.datetime.utcnow().strftime("%Y-%m-%d %H:%M:%S UTC"))
 
 def toggle_trailing_blank_line(depname):
   """If the trailing line is empty, then we'll delete it.
   Otherwise we'll add a blank line."""
   lines = open(depname, "r").readlines()
   if not lines:
-      print >>sys.stderr, "unexpected short file"
+      print("unexpected short file", file=sys.stderr)
       return
 
   if not lines[-1].strip():
@@ -95,7 +96,7 @@ def toggle_trailing_blank_line(depname):
 def get_trailing_blank_line_state(depname):
   lines = open(depname, "r").readlines()
   if not lines:
-      print >>sys.stderr, "unexpected short file"
+      print("unexpected short file", file=sys.stderr)
       return "no blank line"
 
   if not lines[-1].strip():
@@ -108,25 +109,26 @@ def update_nspr_or_nss(tag, depfile, destination, hgpath):
   permanent_patch_dir = destination + '/patches'
   temporary_patch_dir = destination + '.patches'
   if os.path.exists(temporary_patch_dir):
-    print "please clean up leftover directory " + temporary_patch_dir
+    print("please clean up leftover directory " + temporary_patch_dir)
     sys.exit(2)
   warn_if_patch_exists(permanent_patch_dir)
   # protect patch directory from being removed by do_hg_replace
   if os.path.exists(permanent_patch_dir):
     shutil.move(permanent_patch_dir, temporary_patch_dir)
   # now update the destination
-  print "reverting to HG version of %s to get its blank line state" % depfile
+  print("reverting to HG version of %s to get its blank line state" % depfile)
   check_call_noisy([options.hg, 'revert', depfile])
   old_state = get_trailing_blank_line_state(depfile)
-  print "old state of %s is: %s" % (depfile, old_state)
+  print("old state of %s is: %s" % (depfile, old_state))
   do_hg_replace(destination, hgpath, tag, HG_EXCLUSIONS, options.hg)
   new_state = get_trailing_blank_line_state(depfile)
-  print "new state of %s is: %s" % (depfile, new_state)
+  print("new state of %s is: %s" % (depfile, new_state))
   if old_state == new_state:
-    print "toggling blank line in: ", depfile
+    print("toggling blank line in: ", depfile)
     toggle_trailing_blank_line(depfile)
   tag_file = destination + "/TAG-INFO"
-  print >>file(tag_file, "w"), tag
+  with open(tag_file, 'w') as f:
+    f.write(tag)
   # move patch directory back to a subdirectory
   if os.path.exists(temporary_patch_dir):
     shutil.move(temporary_patch_dir, permanent_patch_dir)
@@ -135,12 +137,12 @@ def warn_if_patch_exists(path):
   # If the given patch directory exists and contains at least one file,
   # then print warning and wait for the user to acknowledge.
   if os.path.isdir(path) and os.listdir(path):
-    print "========================================"
-    print "WARNING: At least one patch file exists"
-    print "in directory: " + path
-    print "You must manually re-apply all patches"
-    print "after this script has completed!"
-    print "========================================"
+    print("========================================")
+    print("WARNING: At least one patch file exists")
+    print("in directory: " + path)
+    print("You must manually re-apply all patches")
+    print("after this script has completed!")
+    print("========================================")
     raw_input("Press Enter to continue...")
     return
 
diff --git a/tools/lint/py2.yml b/tools/lint/py2.yml
index 1b241538390a..6d328af8cba2 100644
--- a/tools/lint/py2.yml
+++ b/tools/lint/py2.yml
@@ -4,7 +4,6 @@ py2:
     include: ['.']
     exclude:
         - build
-        - client.py
         - dom
         - editor
         - gfx
diff --git a/tools/lint/py3.yml b/tools/lint/py3.yml
index 10d65400b913..b0fa00c1af17 100644
--- a/tools/lint/py3.yml
+++ b/tools/lint/py3.yml
@@ -5,7 +5,6 @@ py3:
     exclude:
         - browser/app
         - build
-        - client.py
         - dom/canvas/test
         - gfx
         - ipc/ipdl