diff --git a/ci-build.sh b/ci-build.sh
index db59a73..61195aa 100755
--- a/ci-build.sh
+++ b/ci-build.sh
@@ -2,13 +2,13 @@
 
 python3 --version
 py.test --version
-pep8 --version
+python3 -mpep8 --version
 
 # Target directory for all build files
 BUILD=${1:-ci-build}
 mkdir -p $BUILD
 
-pep8 --ignore E501 i3pystatus tests
+python3 -mpep8 --ignore E501 i3pystatus tests
 
 # Check that the setup.py script works
 rm -rf ${BUILD}/test-install ${BUILD}/test-install-bin
diff --git a/i3pystatus/__init__.py b/i3pystatus/__init__.py
index d18ca03..6d578cb 100644
--- a/i3pystatus/__init__.py
+++ b/i3pystatus/__init__.py
@@ -5,6 +5,16 @@ from i3pystatus.core.modules import Module, IntervalModule
 from i3pystatus.core.settings import SettingsBase
 from i3pystatus.core.util import formatp
 
+import logging
+import os
+
+h = logging.FileHandler(".i3pystatus-" + str(os.getpid()), delay=True)
+
+logger = logging.getLogger("i3pystatus")
+logger.addHandler(h)
+logger.setLevel(logging.CRITICAL)
+
+
 __path__ = extend_path(__path__, __name__)
 
 __all__ = [
diff --git a/i3pystatus/core/command.py b/i3pystatus/core/command.py
new file mode 100644
index 0000000..3a7813b
--- /dev/null
+++ b/i3pystatus/core/command.py
@@ -0,0 +1,29 @@
+# from subprocess import CalledProcessError
+import subprocess
+
+
+def run_through_shell(command, enable_shell=False):
+    """
+    Retrieves output of command
+    Returns tuple success (boolean)/ stdout(string) / stderr (string)
+
+    Don't use this function with programs that outputs lots of data since the output is saved
+    in one variable
+    """
+    returncode = None
+    try:
+        proc = subprocess.Popen(command, stderr=subprocess.PIPE, stdout=subprocess.PIPE, shell=enable_shell)
+
+        out, stderr = proc.communicate()
+        out = out.decode("UTF-8")
+        stderr = stderr.decode("UTF-8")
+
+        returncode = proc.returncode
+
+    except OSError as e:
+        out = e.strerror
+        stderr = e.strerror
+    except subprocess.CalledProcessError as e:
+        out = e.output
+
+    return returncode, out, stderr
diff --git a/i3pystatus/core/settings.py b/i3pystatus/core/settings.py
index eae708c..6d67ae6 100644
--- a/i3pystatus/core/settings.py
+++ b/i3pystatus/core/settings.py
@@ -1,6 +1,7 @@
 from i3pystatus.core.util import KeyConstraintDict
 from i3pystatus.core.exceptions import ConfigKeyError, ConfigMissingError
 import inspect
+import logging
 
 
 class SettingsBase:
@@ -18,7 +19,7 @@ class SettingsBase:
     """
 
     settings = (
-        ("enable_log", "Set to true to log error to .i3pystatus-<pid> file"),
+        ("log_level", "Set to true to log error to .i3pystatus-<pid> file"),
     )
 
     """settings should be tuple containing two types of elements:
@@ -31,7 +32,8 @@ class SettingsBase:
     required = tuple()
     """required can list settings which are required"""
 
-    enable_log = False
+    log_level = logging.NOTSET
+    logger = None
 
     def __init__(self, *args, **kwargs):
         def get_argument_dict(args, kwargs):
@@ -71,6 +73,8 @@ class SettingsBase:
         self.__name__ = "{}.{}".format(
             self.__module__, self.__class__.__name__)
 
+        self.logger = logging.getLogger(self.__name__)
+        self.logger.setLevel(self.log_level)
         self.init()
 
     def init(self):
diff --git a/i3pystatus/mail/__init__.py b/i3pystatus/mail/__init__.py
index abf0ba1..e683f0e 100644
--- a/i3pystatus/mail/__init__.py
+++ b/i3pystatus/mail/__init__.py
@@ -1,7 +1,5 @@
-import subprocess
-
 from i3pystatus import SettingsBase, IntervalModule
-from i3pystatus.core.util import internet, require
+from i3pystatus.core.command import run_through_shell
 
 
 class Backend(SettingsBase):
@@ -69,7 +67,9 @@ class Mail(IntervalModule):
 
     def on_leftclick(self):
         if self.email_client:
-            subprocess.Popen(self.email_client.split())
+            retcode, _, stderr = run_through_shell(self.email_client)
+            if retcode != 0 and stderr:
+                self.logger.error(stderr)
 
     def on_rightclick(self):
         self.run()
diff --git a/i3pystatus/shell.py b/i3pystatus/shell.py
index 571521f..5cea607 100644
--- a/i3pystatus/shell.py
+++ b/i3pystatus/shell.py
@@ -1,5 +1,8 @@
 from i3pystatus import IntervalModule
-from subprocess import check_output, CalledProcessError
+from i3pystatus.core.command import run_through_shell
+import logging
+
+# logger = logging.getLogger(__name__)
 
 
 class Shell(IntervalModule):
@@ -19,21 +22,17 @@ class Shell(IntervalModule):
     required = ("command",)
 
     def run(self):
-        try:
-            out = check_output(self.command, shell=True)
-            color = self.color
-        except CalledProcessError as e:
-            out = e.output
-            color = self.error_color
+        retvalue, out, stderr = run_through_shell(self.command, enable_shell=True)
 
-        out = out.decode("UTF-8").replace("\n", " ")
-        try:
-            if out[-1] == " ":
-                out = out[:-1]
-        except:
-            out = ""
+        if retvalue != 0:
+            self.logger.error(stderr if stderr else "Unknown error")
+
+        if out:
+            out.replace("\n", " ").strip()
+        elif stderr:
+            out = stderr
 
         self.output = {
-            "full_text": out,
-            "color": color
+            "full_text": out if out else "Command `%s` returned %d" % (self.command, retvalue),
+            "color": self.color if retvalue == 0 else self.error_color
         }
diff --git a/tests/test_core_modules.py b/tests/test_core_modules.py
index 84b40cb..2ab34f8 100644
--- a/tests/test_core_modules.py
+++ b/tests/test_core_modules.py
@@ -11,7 +11,8 @@ class IntervalModuleMetaTest(unittest.TestCase):
     def test_no_settings(self):
         class NoSettings(IntervalModule):
             pass
-        self.assertTrue('interval' in NoSettings.settings)
+        for element in ('interval', ):
+            self.assertIn(element, NoSettings.settings)
 
     def test_no_interval_setting(self):
         class NoIntervalSetting(IntervalModule):
@@ -20,9 +21,9 @@ class IntervalModuleMetaTest(unittest.TestCase):
                          (('option', 'desc'), 'interval'))
 
     def test_settings_with_interval(self):
-        class SettingsInteval(IntervalModule):
+        class SettingsInterval(IntervalModule):
             settings = ('option', 'interval')
-        self.assertEqual(SettingsInteval.settings, ('option', 'interval'))
+        self.assertEqual(SettingsInterval.settings, ('option', 'interval'))
 
     def test_settings_with_interval_desc(self):
         class SetttingsIntervalDesc(IntervalModule):
diff --git a/tests/test_shell.py b/tests/test_shell.py
new file mode 100644
index 0000000..ec9e388
--- /dev/null
+++ b/tests/test_shell.py
@@ -0,0 +1,24 @@
+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+
+import unittest
+import logging
+
+from i3pystatus.shell import Shell
+from i3pystatus.core.command import run_through_shell
+
+
+class ShellModuleMetaTest(unittest.TestCase):
+
+    valid_output = "hello world"
+
+    def test_shell_correct_output(self):
+        # ShellTest test
+        # http://python.readthedocs.org/en/latest/library/unittest.html
+        retcode, out, err = run_through_shell("echo '%s'" % (self.valid_output), enable_shell=True)
+        self.assertTrue(retcode == 0)
+        self.assertEqual(out.strip(), self.valid_output)
+
+    def test_program_failure(self):
+        success, out, err = run_through_shell("thisshouldtriggeranerror")
+        self.assertFalse(success)