ignore the single quotes string when parsing

IPython/core/tests/test_interactiveshell.py

@@ -211,11 +211,13 b' class InteractiveShellTestCase(unittest.TestCase):'
         self.assertEqual(ip.var_expand(u'echo {f}'), u'echo Ca\xf1o')
         self.assertEqual(ip.var_expand(u'echo {f[:-1]}'), u'echo Ca\xf1')
         self.assertEqual(ip.var_expand(u'echo {1*2}'), u'echo 2')
+        
+        self.assertEqual(ip.var_expand(u"grep x | awk '{print $1}'"), u"grep x | awk '{print $1}'")
 
         ip.user_ns['f'] = b'Ca\xc3\xb1o'
         # This should not raise any exception:
         ip.var_expand(u'echo $f')
-    
+   
     def test_var_expand_local(self):
         """Test local variable expansion in !system and %magic calls"""
         # !system

IPython/utils/text.py

@@ -592,7 +592,7 b' class DollarFormatter(FullEvalFormatter):'
         In [4]: f.format('$a or {b}', a=1, b=2)
         Out[4]: '1 or 2'
     """
-    _dollar_pattern = re.compile("(.*?)\$(\$?[\w\.]+)")
+    _dollar_pattern_ignore_single_quote = re.compile("(.*?)\$(\$?[\w\.]+)(?=([^']*'[^']*')*[^']*$)")
     def parse(self, fmt_string):
         for literal_txt, field_name, format_spec, conversion \
                     in Formatter.parse(self, fmt_string):
@@ -600,7 +600,7 b' class DollarFormatter(FullEvalFormatter):'
             # Find $foo patterns in the literal text.
             continue_from = 0
             txt = ""
-            for m in self._dollar_pattern.finditer(literal_txt):
+            for m in self._dollar_pattern_ignore_single_quote.finditer(literal_txt):
                 new_txt, new_field = m.group(1,2)
                 # $$foo --> $foo
                 if new_field.startswith("$"):