diff --git a/thefuck/rules/pacman.py b/thefuck/rules/pacman.py
index f709895..4115798 100644
--- a/thefuck/rules/pacman.py
+++ b/thefuck/rules/pacman.py
@@ -1,14 +1,15 @@
 import subprocess
+from thefuck.utils import DEVNULL
 
 
 def __command_available(command):
     try:
-        subprocess.check_output([command], stderr=subprocess.DEVNULL)
+        subprocess.check_output([command], stderr=DEVNULL)
         return True
     except subprocess.CalledProcessError:
         # command exists but is not happy to be called without any argument
         return True
-    except FileNotFoundError:
+    except OSError:
         return False
 
 
diff --git a/thefuck/shells.py b/thefuck/shells.py
index c0bb089..1d128cd 100644
--- a/thefuck/shells.py
+++ b/thefuck/shells.py
@@ -8,9 +8,7 @@ from subprocess import Popen, PIPE
 from time import time
 import os
 from psutil import Process
-
-
-FNULL = open(os.devnull, 'w')
+from .utils import DEVNULL
 
 
 class Generic(object):
@@ -58,7 +56,7 @@ class Bash(Generic):
         return name, value
 
     def _get_aliases(self):
-        proc = Popen('bash -ic alias', stdout=PIPE, stderr=FNULL, shell=True)
+        proc = Popen('bash -ic alias', stdout=PIPE, stderr=DEVNULL, shell=True)
         return dict(
             self._parse_alias(alias)
             for alias in proc.stdout.read().decode('utf-8').split('\n')
@@ -80,7 +78,7 @@ class Zsh(Generic):
         return name, value
 
     def _get_aliases(self):
-        proc = Popen('zsh -ic alias', stdout=PIPE, stderr=FNULL, shell=True)
+        proc = Popen('zsh -ic alias', stdout=PIPE, stderr=DEVNULL, shell=True)
         return dict(
             self._parse_alias(alias)
             for alias in proc.stdout.read().decode('utf-8').split('\n')
diff --git a/thefuck/utils.py b/thefuck/utils.py
index 7ee66c2..3247111 100644
--- a/thefuck/utils.py
+++ b/thefuck/utils.py
@@ -4,6 +4,9 @@ import six
 from .types import Command
 
 
+DEVNULL = open(os.devnull, 'w')
+
+
 def which(program):
     """Returns `program` path or `None`."""