diff --git a/mininet/cli.py b/mininet/cli.py
index ed605500272cb7792ab5924c2952fc651eb130a2..94489862f967090f73ab89889d693c28aae6ac2b 100644
--- a/mininet/cli.py
+++ b/mininet/cli.py
@@ -36,7 +36,7 @@
 
 from mininet.log import info, output, error
 from mininet.term import makeTerms, runX11
-from mininet.util import ( quietRun, isShellBuiltin, dumpNodeConnections,
+from mininet.util import ( quietRun, dumpNodeConnections,
                          dumpPorts )
 
 class CLI( Cmd ):
diff --git a/mininet/net.py b/mininet/net.py
index 6defddba2babbc9786036e93223a46fb88ba4e01..3784af1a97edc8ccf74e062fb66266dfc9a463c6 100755
--- a/mininet/net.py
+++ b/mininet/net.py
@@ -91,7 +91,7 @@
 import select
 import signal
 import random
-import copy
+
 from time import sleep
 from itertools import chain, groupby
 from math import ceil
diff --git a/mininet/node.py b/mininet/node.py
index 33ee3cc1fe0cf7f9135b96f6e34ed6b406485b10..330097f60a527f550b53b3bc359b5215a838d47e 100644
--- a/mininet/node.py
+++ b/mininet/node.py
@@ -51,7 +51,7 @@
 import re
 import signal
 import select
-from subprocess import Popen, PIPE, STDOUT
+from subprocess import Popen, PIPE
 from operator import or_
 from time import sleep
 
diff --git a/mininet/nodelib.py b/mininet/nodelib.py
index dc126bed18a00c38807166d0bb1320a89f342435..54ec1936e7242d610a9bb7763e00409a5f814ea9 100644
--- a/mininet/nodelib.py
+++ b/mininet/nodelib.py
@@ -5,7 +5,7 @@
 """
 
 from mininet.node import Node, Switch
-from mininet.log import setLogLevel, info
+from mininet.log import info
 from mininet.moduledeps import pathCheck