diff -ur fusil.orig/doc/c_tools.rst fusil.patched/doc/c_tools.rst
--- fusil.orig/doc/c_tools.rst	2008-09-12 01:43:29.000000000 +0200
+++ fusil.patched/doc/c_tools.rst	2008-12-20 13:55:16.000000000 +0100
@@ -10,7 +10,7 @@
    >>> quoteString('Hello World\n\0')
    '"Hello World\\n\\0"'
    >>> encodeUTF32("Hello")
-   'H\x00\x00\x00e\x00\x00\x00l\x00\x00\x00l\x00\x00\x00o\x00\x00\x00'
+   b'H\x00\x00\x00e\x00\x00\x00l\x00\x00\x00l\x00\x00\x00o\x00\x00\x00'
 
 encodeUTF32() use host endian.
 
diff -ur fusil.orig/fusil/bits.py fusil.patched/fusil/bits.py
--- fusil.orig/fusil/bits.py	2008-09-07 14:56:22.000000000 +0200
+++ fusil.patched/fusil/bits.py	2008-12-20 13:55:16.000000000 +0100
@@ -64,19 +64,19 @@
     r"""
     Convert a bytes string into an unsigned integer.
 
-    >>> chr(bytes2uint('*', BIG_ENDIAN))
+    >>> chr(bytes2uint(b'*', BIG_ENDIAN))
     '*'
-    >>> bytes2uint("\x00\x01\x02\x03", BIG_ENDIAN) == 0x10203
+    >>> bytes2uint(b"\x00\x01\x02\x03", BIG_ENDIAN) == 0x10203
     True
-    >>> bytes2uint("\x2a\x10", LITTLE_ENDIAN) == 0x102a
+    >>> bytes2uint(b"\x2a\x10", LITTLE_ENDIAN) == 0x102a
     True
-    >>> bytes2uint("\xff\x14\x2a\x10", BIG_ENDIAN) == 0xff142a10
+    >>> bytes2uint(b"\xff\x14\x2a\x10", BIG_ENDIAN) == 0xff142a10
     True
-    >>> bytes2uint("\x00\x01\x02\x03", LITTLE_ENDIAN) == 0x3020100
+    >>> bytes2uint(b"\x00\x01\x02\x03", LITTLE_ENDIAN) == 0x3020100
     True
-    >>> bytes2uint("\xff\x14\x2a\x10\xab\x00\xd9\x0e", BIG_ENDIAN) == 0xff142a10ab00d90e
+    >>> bytes2uint(b"\xff\x14\x2a\x10\xab\x00\xd9\x0e", BIG_ENDIAN) == 0xff142a10ab00d90e
     True
-    >>> bytes2uint("\xff\xff\xff\xff\xff\xff\xff\xff", BIG_ENDIAN) == (2**64-1)
+    >>> bytes2uint(b"\xff\xff\xff\xff\xff\xff\xff\xff", BIG_ENDIAN) == (2**64-1)
     True
     """
     assert 1 <= len(data) <= 32   # arbitrary limit: 256 bits
diff -ur fusil.orig/fusil/bytes_generator.py fusil.patched/fusil/bytes_generator.py
--- fusil.orig/fusil/bytes_generator.py	2008-12-20 13:53:18.000000000 +0100
+++ fusil.patched/fusil/bytes_generator.py	2008-12-20 13:55:16.000000000 +0100
@@ -19,7 +19,7 @@
 from random import choice, randint
 
 def createBytesSet(start, stop):
-    return set(''.join(chr(code) for code in range(start, stop+1)))
+    return set(range(start, stop+1))
 
 # ASCII codes 0..255
 ASCII8 = createBytesSet(0, 255)
@@ -34,12 +34,12 @@
 PRINTABLE_ASCII = createBytesSet(32, 126)
 
 # Letters and digits
-UPPER_LETTERS = set('ABCDEFGHIJKLMNOPQRSTUVWXYZ')
-LOWER_LETTERS = set('abcdefghijklmnopqrstuvwxyz')
+UPPER_LETTERS = set(b'ABCDEFGHIJKLMNOPQRSTUVWXYZ')
+LOWER_LETTERS = set(b'abcdefghijklmnopqrstuvwxyz')
 LETTERS = UPPER_LETTERS | LOWER_LETTERS
-DECIMAL_DIGITS = set('0123456789')
-HEXADECIMAL_DIGITS = DECIMAL_DIGITS | set('abcdefABCDEF')
-PUNCTUATION = set(' .,-;?!:(){}[]<>\'"/\\')
+DECIMAL_DIGITS = set(b'0123456789')
+HEXADECIMAL_DIGITS = DECIMAL_DIGITS | set(b'abcdefABCDEF')
+PUNCTUATION = set(b' .,-;?!:(){}[]<>\'"/\\')
 
 class Generator:
     def __init__(self, min_length, max_length):
@@ -65,11 +65,11 @@
     def _createValue(self, length):
         bytes_list = list(self.bytes_set)
         if len(bytes_list) != 1:
-            return ''.join( choice(bytes_list) for index in range(length) )
+            return bytes( choice(bytes_list) for index in range(length) )
         else:
-            return bytes_list[0] * length
+            return bytes((bytes_list[0],)) * length
 
 class LengthGenerator(BytesGenerator):
     def __init__(self, min_length, max_length):
-        BytesGenerator.__init__(self, min_length, max_length, set('A'))
+        BytesGenerator.__init__(self, min_length, max_length, set(b'A'))
 
diff -ur fusil.orig/fusil/c_tools.py fusil.patched/fusil/c_tools.py
--- fusil.orig/fusil/c_tools.py	2008-12-20 13:53:20.000000000 +0100
+++ fusil.patched/fusil/c_tools.py	2008-12-20 13:55:16.000000000 +0100
@@ -18,7 +18,7 @@
     data = []
     for character in text:
         data.append( pack('I', ord(character)) )
-    return ''.join(data)
+    return b''.join(data)
 
 def quoteString(text):
     data = []
diff -ur fusil.orig/fusil/file_watch.py fusil.patched/fusil/file_watch.py
--- fusil.orig/fusil/file_watch.py	2008-12-20 13:53:24.000000000 +0100
+++ fusil.patched/fusil/file_watch.py	2008-12-20 13:55:16.000000000 +0100
@@ -90,7 +90,7 @@
             if isinstance(text, str):
                 text = text.encode("ASCII")
             regex = re.escape(text)
-            regex = r'(?:^|\W)' + regex + r'(?:$|\W)'
+            regex = br'(?:^|\W)' + regex + br'(?:$|\W)'
             match = re.compile(regex, re.IGNORECASE).search
             yield (text, score, match)
 
@@ -121,12 +121,12 @@
     def splitlines(self, data):
         lines = data.splitlines(1)
         for index, line in enumerate(lines):
-            if index == len(lines)-1 and line[-1] not in '\n\r':
+            if index == len(lines)-1 and line[-1] not in b'\n\r':
                 self.buffer.append(line)
                 return
             if index == 0 and self.buffer:
                 self.buffer.append(line)
-                line = ''.join(self.buffer)
+                line = b''.join(self.buffer)
                 self.buffer = []
             yield line.rstrip()
 
diff -ur fusil.orig/fusil/mangle_op.py fusil.patched/fusil/mangle_op.py
--- fusil.orig/fusil/mangle_op.py	2008-07-10 01:39:14.000000000 +0200
+++ fusil.patched/fusil/mangle_op.py	2008-12-20 13:55:16.000000000 +0100
@@ -2,22 +2,22 @@
     values = (
         # Special values in big endian
         # SPECIAL_VALUES will contains value in big endian and little endian
-        "\x00",
-        "\x00\x00",
-        "\x01",
-        "\x00\x01",
-        "\x7f",
-        "\x7f\xff",
-        "\x7f\xff\xff\xff",
-        "\x80",
-        "\x80\x00",
-        "\x80\x00\x00\x00",
-        "\xfe",
-        "\xfe\xff",
-        "\xfe\xff\xff\xff",
-        "\xff",
-        "\xff\xff",
-        "\xff\xff\xff\xff",
+        b"\x00",
+        b"\x00\x00",
+        b"\x01",
+        b"\x00\x01",
+        b"\x7f",
+        b"\x7f\xff",
+        b"\x7f\xff\xff\xff",
+        b"\x80",
+        b"\x80\x00",
+        b"\x80\x00\x00\x00",
+        b"\xfe",
+        b"\xfe\xff",
+        b"\xfe\xff\xff\xff",
+        b"\xff",
+        b"\xff\xff",
+        b"\xff\xff\xff\xff",
     )
     result = []
     for item in values:
diff -ur fusil.orig/fusil/process/replay_python.py fusil.patched/fusil/process/replay_python.py
--- fusil.orig/fusil/process/replay_python.py	2008-12-20 13:53:54.000000000 +0100
+++ fusil.patched/fusil/process/replay_python.py	2008-12-20 13:55:16.000000000 +0100
@@ -40,9 +40,9 @@
     cwd + u'b'
     """
     result = []
-    if isinstance(value, str):
+    if isinstance(value, bytes):
         pattern = cwd_bytes
-        replace = 'cwd_bytes'
+        replace = b'cwd_bytes'
     else:
         pattern = cwd
         replace = 'cwd'
@@ -331,7 +331,7 @@
 
         need_cwd_bytes = False
         for value in itertools.chain(arguments, iter(env.values())):
-            if not isinstance(value, str):
+            if not isinstance(value, bytes):
                 continue
             if cwd_bytes not in value:
                 continue