diff --git a/jupytext/magics.py b/jupytext/magics.py
index a946e96ce..9dbfc5d0e 100644
--- a/jupytext/magics.py
+++ b/jupytext/magics.py
@@ -18,7 +18,8 @@
 # Commands starting with a question or exclamation mark have to be escaped
 _PYTHON_HELP_OR_BASH_CMD = re.compile(r"^(# |#)*(\?|!)\s*[A-Za-z]")
 
-_PYTHON_MAGIC_CMD = re.compile(r"^(# |#)*({})(\s|$)".format('|'.join(
+# A bash command not followed by an equal sign or a parenthesis is a magic command
+_PYTHON_MAGIC_CMD = re.compile(r"^(# |#)*({})($|\s$|\s[^=,])".format('|'.join(
     # posix
     ['cat', 'cp', 'mv', 'rm', 'rmdir', 'mkdir'] +
     # windows
diff --git a/tests/test_escape_magics.py b/tests/test_escape_magics.py
index 21acab138..60a69c0ce 100644
--- a/tests/test_escape_magics.py
+++ b/tests/test_escape_magics.py
@@ -108,13 +108,15 @@ def test_force_comment_using_contents_manager(tmpdir):
         assert '%pylab inline' in stream.read().splitlines()
 
 
-@pytest.mark.parametrize('magic_cmd', ['ls', '!ls', 'ls -al', '!whoami', '# ls', '# mv a b', '! mkdir tmp'])
+@pytest.mark.parametrize('magic_cmd', ['ls', '!ls', 'ls -al', '!whoami', '# ls', '# mv a b', '! mkdir tmp',
+                                       'cat', 'cat ', 'cat hello.txt', 'cat --option=value hello.txt'])
 def test_comment_bash_commands_in_python(magic_cmd):
     assert comment_magic([magic_cmd]) == ['# ' + magic_cmd]
     assert uncomment_magic(['# ' + magic_cmd]) == [magic_cmd]
 
 
-@pytest.mark.parametrize('not_magic_cmd', ['copy(a)', 'copy.deepcopy'])
+@pytest.mark.parametrize('not_magic_cmd',
+                         ['copy(a)', 'copy.deepcopy', 'cat = 3', 'cat=5', 'cat, other = 5,3', 'cat(5)'])
 def test_do_not_comment_python_cmds(not_magic_cmd):
     assert comment_magic([not_magic_cmd]) == [not_magic_cmd]
     assert uncomment_magic([not_magic_cmd]) == [not_magic_cmd]