diff --git a/revelation/argument_parser.py b/revelation/argument_parser.py
index 507744f..494b91a 100644
--- a/revelation/argument_parser.py
+++ b/revelation/argument_parser.py
@@ -31,6 +31,11 @@
 """
 
 
+class DoNotInterpretError(Exception):
+    def __init__(self):
+        pass
+
+
 def cli_parser(argv, simulator, debug_enabled):
     filename_index = 0
     debug_flags = []
@@ -52,7 +57,7 @@ def cli_parser(argv, simulator, debug_enabled):
             if token == '--help' or token == '-h':
                 print (USAGE_TEXT % (simulator.arch_name, argv[0], argv[0],
                                      argv[0], argv[0], argv[0]))
-                raise SystemExit
+                raise DoNotInterpretError
             elif token == '--time' or token == '-t':
                 simulator.collect_times = True
             elif token == '--debug' or token == '-d':
@@ -65,7 +70,7 @@ def cli_parser(argv, simulator, debug_enabled):
                 prev_token = token
             elif token[:1] == '-':
                 print 'Unknown argument %s' % token
-                raise SystemExit
+                raise SyntaxError
             else:
                 filename_index = index + 1
                 break
@@ -79,7 +84,7 @@ def cli_parser(argv, simulator, debug_enabled):
                     simulator.user_environment = True
                 else:
                     print ('--env can be OPERATING or USER.')
-                    raise SystemExit
+                    raise ValueError
             elif prev_token == '--ext-base' or prev_token == '-b':
                 simulator.ext_base =int(token, 16)
             elif prev_token == '--cols' or prev_token == '-c':
@@ -99,5 +104,5 @@ def cli_parser(argv, simulator, debug_enabled):
             prev_token = ''
     if filename_index == 0:
         print 'You must supply a file name'
-        raise SystemExit
+        raise SyntaxError
     return argv[filename_index], jit, debug_flags
diff --git a/revelation/sim.py b/revelation/sim.py
index ff5cea1..27be264 100644
--- a/revelation/sim.py
+++ b/revelation/sim.py
@@ -3,7 +3,7 @@
 from pydgin.misc import FatalError
 from pydgin.sim import Sim, init_sim
 
-from revelation.argument_parser import cli_parser
+from revelation.argument_parser import cli_parser, DoNotInterpretError
 from revelation.elf_loader import load_program
 from revelation.instruction import Instruction
 from revelation.isa import decode, reg_map
@@ -83,7 +83,12 @@ def get_entry_point(self):
         def entry_point(argv):
             if self.jit_enabled:
                 set_param(self.jitdriver, 'trace_limit', self.default_trace_limit)
-            fname, jit, flags = cli_parser(argv, self, Debug.global_enabled)
+            try:
+                fname, jit, flags = cli_parser(argv, self, Debug.global_enabled)
+            except DoNotInterpretError:  # CLI option such as --help or -h.
+                return 0
+            except (SyntaxError, ValueError):
+                return 1
             if jit:  # pragma: no cover
                 set_user_param(self.jitdriver, jit)
             self.debug = Debug(flags, 0)
@@ -91,7 +96,7 @@ def entry_point(argv):
                 elf_file = open(fname, 'rb')
             except IOError:
                 print 'Could not open file %s' % fname
-                raise SystemExit
+                return 1
             self.init_state(elf_file, fname, False)
             for state in self.states:  # FIXME: Interleaved log.
                 self.debug.set_state(state)
diff --git a/revelation/test/test_argument_parser.py b/revelation/test/test_argument_parser.py
index 3fd9a9d..a960065 100644
--- a/revelation/test/test_argument_parser.py
+++ b/revelation/test/test_argument_parser.py
@@ -1,4 +1,4 @@
-from revelation.argument_parser import USAGE_TEXT
+from revelation.argument_parser import USAGE_TEXT, DoNotInterpretError
 from revelation.sim import Revelation
 
 import os.path
@@ -89,8 +89,7 @@ def test_argv_flags_with_no_args(argv, capfd):
 def test_argv_with_errors(argv, expected, capfd):
     revelation = Revelation()
     entry_point = revelation.get_entry_point()
-    with pytest.raises(SystemExit):
-        entry_point(argv)
+    entry_point(argv)
     out, err = capfd.readouterr()
     assert err == ''
     assert out == expected
@@ -102,8 +101,7 @@ def test_argv_help(argv, capfd):
     expected = (USAGE_TEXT % ('revelation', 'sim.py', 'sim.py', 'sim.py',
                               'sim.py', 'sim.py') + '\n')
     entry_point = revelation.get_entry_point()
-    with pytest.raises(SystemExit):
-        entry_point(argv)
+    entry_point(argv)
     out, err = capfd.readouterr()
     assert err == ''
     assert out == expected