diff --git a/src/cowrie/commands/cat.py b/src/cowrie/commands/cat.py
index 6cace5b2..a4f7e6fa 100644
--- a/src/cowrie/commands/cat.py
+++ b/src/cowrie/commands/cat.py
@@ -62,26 +62,33 @@ class command_cat(HoneyPotCommand):
                         raise FileNotFound
                 except FileNotFound:
                     self.errorWrite('cat: {}: No such file or directory\n'.format(arg))
-
+            self.exit()
+        elif self.input_data is not None:
+            self.output(self.input_data)
             self.exit()
 
     def output(self, input):
         """
         This is the cat output, with optional line numbering
         """
-        if 'decode' in dir(input):
-            input = input.decode('UTF-8')
-        if not isinstance(input, str):
-            pass
+        if input is None:
+            return
 
-        lines = input.split('\n')
-        if lines[-1] == "":
+        if isinstance(input, str):
+            input = input.encode('utf8')
+        elif isinstance(input, bytes):
+            pass
+        else:
+            log.msg("unusual cat input {}".format(repr(input)))
+
+        lines = input.split(b'\n')
+        if lines[-1] == b'':
             lines.pop()
         for line in lines:
             if self.number:
-                self.write("{:>6}  ".format(self.linenumber))
+                self.write('{:>6}  '.format(self.linenumber))
                 self.linenumber = self.linenumber + 1
-            self.write(line + '\n')
+            self.writeBytes(line + b'\n')
 
     def lineReceived(self, line):
         """
diff --git a/src/cowrie/commands/fs.py b/src/cowrie/commands/fs.py
index c67dedda..bf556ef0 100644
--- a/src/cowrie/commands/fs.py
+++ b/src/cowrie/commands/fs.py
@@ -34,12 +34,11 @@ class command_grep(HoneyPotCommand):
             self.errorWrite("grep: {}: No such file or directory\n".format(filename))
 
     def grep_application(self, contents, match):
-        match = os.path.basename(match)
-        match = match.replace('\"', '')
+        match = os.path.basename(match).replace('\"', '').encode('utf8')
+        matches = re.compile(match)
         contentsplit = contents.split(b'\n')
-        matches = re.compile('.*' + match + '.*')
         for line in contentsplit:
-            if matches.match(line.decode()):
+            if matches.search(line):
                 self.writeBytes(line + b'\n')
 
     def help(self):
diff --git a/src/cowrie/test/test_cat.py b/src/cowrie/test/test_cat.py
index 2a614cf5..fd9f2829 100644
--- a/src/cowrie/test/test_cat.py
+++ b/src/cowrie/test/test_cat.py
@@ -47,12 +47,12 @@ class ShellCatCommandTests(unittest.TestCase):
 
     def test_cat_command_003(self):
         """
-        test ignore stdin when called without '-'
+        test without arguments, read stdin only and quit
         """
-        self.proto.lineReceived(b'echo whatever | cat\n')
-        self.proto.lineReceived(b'test\n')
+        self.proto.lineReceived(b'echo 1 | cat\n')
+        self.proto.lineReceived(b'echo 2\n')
         self.proto.handle_CTRL_D()
-        self.assertEquals(self.tr.value(), b'test\n' + PROMPT)
+        self.assertEquals(self.tr.value(), b'1\n' + PROMPT + b'2\n' + PROMPT)
 
     def test_cat_command_004(self):
         """