Merge pull request #2131 from doda/master

Add option append (-a) to %save

IPython/core/magics/code.py

@@ -61,6 +61,8 b' class CodeMagics(Magics):'
           -f: force overwrite.  If file exists, %save will prompt for overwrite
           unless -f is given.
 
+          -a: append to the file instead of overwriting it.
+
         This function uses the same syntax as %history for input ranges,
         then saves the lines to the filename you specify.
 
@@ -70,14 +72,17 b' class CodeMagics(Magics):'
         If `-r` option is used, the default extension is `.ipy`.
         """
 
-        opts,args = self.parse_options(parameter_s,'fr',mode='list')
+        opts,args = self.parse_options(parameter_s,'fra',mode='list')
         raw = 'r' in opts
         force = 'f' in opts
+        append = 'a' in opts
+        mode = 'a' if append else 'w'
         ext = u'.ipy' if raw else u'.py'
         fname, codefrom = unquote_filename(args[0]), " ".join(args[1:])
         if not fname.endswith((u'.py',u'.ipy')):
             fname += ext
-        if os.path.isfile(fname) and not force:
+        file_exists = os.path.isfile(fname)
+        if file_exists and not force and not append:
             try:
                 overwrite = self.shell.ask_yes_no('File `%s` exists. Overwrite (y/[N])? ' % fname, default='n')
             except StdinNotImplementedError:
@@ -91,9 +96,14 b' class CodeMagics(Magics):'
         except (TypeError, ValueError) as e:
             print e.args[0]
             return
-        with io.open(fname,'w', encoding="utf-8") as f:
-            f.write(u"# coding: utf-8\n")
-            f.write(py3compat.cast_unicode(cmds))
+        out = py3compat.cast_unicode(cmds)
+        with io.open(fname, mode, encoding="utf-8") as f:
+            if not file_exists or not append:
+                f.write(u"# coding: utf-8\n")
+            f.write(out)
+            # make sure we end on a newline
+            if not out.endswith(u'\n'):
+                f.write(u'\n')
         print 'The following commands were written to file `%s`:' % fname
         print cmds
 

IPython/core/tests/test_history.py

@@ -95,7 +95,7 b' def test_history():'
             ip.magic("save " + testfilename + " ~1/1-3")
             with py3compat.open(testfilename, encoding='utf-8') as testfile:
                 nt.assert_equal(testfile.read(),
-                                        u"# coding: utf-8\n" + u"\n".join(hist))
+                                        u"# coding: utf-8\n" + u"\n".join(hist)+u"\n")
 
             # Duplicate line numbers - check that it doesn't crash, and
             # gets a new session

IPython/core/tests/test_magic.py

@@ -742,3 +742,23 b' def test_alias_magic():'
     ip.run_line_magic('alias_magic', '--line env_alias env')
     nt.assert_equal(ip.run_line_magic('env', ''),
                     ip.run_line_magic('env_alias', ''))
+
+def test_save():
+    """Test %save."""
+    ip = get_ipython()
+    ip.history_manager.reset()   # Clear any existing history.
+    cmds = [u"a=1", u"def b():\n  return a**2", u"print(a, b())"]
+    for i, cmd in enumerate(cmds, start=1):
+        ip.history_manager.store_inputs(i, cmd)
+    with TemporaryDirectory() as tmpdir:
+        file = os.path.join(tmpdir, "testsave.py")
+        ip.run_line_magic("save", "%s 1-10" % file)
+        with open(file) as f:
+            content = f.read()
+            nt.assert_equal(content.count(cmds[0]), 1)
+            nt.assert_true('coding: utf-8' in content)
+        ip.run_line_magic("save", "-a %s 1-10" % file)
+        with open(file) as f:
+            content = f.read()
+            nt.assert_equal(content.count(cmds[0]), 2)
+            nt.assert_true('coding: utf-8' in content)