diff --git a/command.py b/command.py
index 83720f8..69d8b54 100644
--- a/command.py
+++ b/command.py
@@ -13,7 +13,7 @@ class InlineCommand(Span, Command):
 			if len(content) == 1 and isinstance(content[0], Para):
 				return Span(*content[0].content)
 			else:
-				return Div(*content)
+				raise SyntaxError(f"The command {self.attributes['c']} returned multiple Paragraphs and must be executed using `::: {{c={self.attributes['c']}}}\\n:::`.")
 	pass
 
 class MultilineCommand(Div, Command):
diff --git a/formatitko.py b/formatitko.py
index 341e3fa..626bfc1 100755
--- a/formatitko.py
+++ b/formatitko.py
@@ -1,16 +1,16 @@
 #!/usr/bin/env python3
 
-# Import local files
-from whitespace import *
-from command import *
-from util import *
-import builtin_commands
 
 from panflute import *
 import re
 import sys
 from typing import List
 
+# Import local files
+from whitespace import *
+from command import *
+from util import *
+
 from mj_show import show
 
 flags = ["dog"]
@@ -20,14 +20,14 @@ def executeCommand(source: Code, element: Element) -> List[Element]:
 	mode = 'empty'
 	text = ""
 	content = []
-	def print(s: str):
+	def print(s: str=""):
 		nonlocal mode, text
 		if mode == 'elements':
 			raise SyntaxError("Cannot use `print` and `appendChild` in one command at the same time.")
 		mode = 'text'
 		text += s
 	
-	def println(s: str):
+	def println(s: str=""):
 		print(s+"\n")
 
 	def appendChild(e: Element):
@@ -52,6 +52,9 @@ def executeCommand(source: Code, element: Element) -> List[Element]:
 
 def transform(e: Element, doc: Doc) -> Element: # Returns next sibling element to transform
 	"""Transform the AST, making format-agnostic changes."""
+
+	global commands
+	global flags
 	
 	if isinstance(e, Whitespace) and bavlna(e):
 		e = NBSP()
@@ -60,11 +63,11 @@ def transform(e: Element, doc: Doc) -> Element: # Returns next sibling element t
 		# `if` attribute. Only show this element if flag is set.
 		if "if" in e.attributes:
 			if not e.attributes["if"] in flags:
-				return Null()
+				return nullify(e)
 		# `ifn` attribute. Only show this element if flag is NOT set
 		if "ifn" in e.attributes:
 			if e.attributes["ifn"] in flags:
-				return Null()
+				return nullify(e)
 		
 		# `c` attribute. Execute a command with the name saved in this attribute.
 		if (isinstance(e, Div) or isinstance(e, Span)) and "c" in e.attributes:
@@ -72,32 +75,54 @@ def transform(e: Element, doc: Doc) -> Element: # Returns next sibling element t
 				e = MultilineCommand(*e.content, identifier=e.identifier, classes=e.classes, attributes=e.attributes)
 			else:
 				e = InlineCommand(*e.content, identifier=e.identifier, classes=e.classes, attributes=e.attributes)
-				print(f"Created inline command {e}")
 	
 	
 	# Execute python code inside source code block
 	if isinstance(e, CodeBlock) and hasattr(e, "classes") and "python" in e.classes and "run" in e.classes:
 		exec(e.text)
-		return Null()
+		return nullify(e)
 	
-	# Define commands
+	## Define commands
 	# TODO: def/longdef?
 	if isinstance(e, CodeBlock) and hasattr(e, "classes") and "python" in e.classes and hasattr(e, "attributes"):
 		if "define" in e.attributes:
 			if not e.attributes["define"] in commands:
 				commands[e.attributes["define"]] = compile(e.text, '<string>', 'exec')
-				return Null()
+				return nullify(e)
 			else:
 				raise NameError(f"Command already defined: '{e.attributes['define']}'")
 		if "redefine" in e.attributes:
 			commands[e.attributes["redefine"]] = compile(e.text, '<string>', 'exec')
-			return Null()
+			return nullify(e)
 	
-	# Handle special command shorthand [!commandname]{}
-	if isinstance(e, Span) and len(e.content) == 1 and isinstance(e.content[0], Str) and re.match(r"^![\w.]+$", e.content[0].text):
-		e = InlineCommand(identifier=e.identifier, classes=e.classes, attributes={**e.attributes, "c": e.content[0].text[1:]})
-
-	# Execute commands
+	if isinstance(e, Span) and len(e.content) == 1 and isinstance(e.content[0], Str):
+		print(isinstance(e, Span))
+		## Handle special command shorthand [!commandname]{}
+		if re.match(r"^![\w.]+$", e.content[0].text):
+			e = InlineCommand(identifier=e.identifier, classes=e.classes, attributes={**e.attributes, "c": e.content[0].text[1:]})
+
+		## Handle include [>path/file.md]{} TODO: implement properly as commands
+		# This is for including content from files with their own flags
+		# and commands without affecting the state of the current
+		# document.
+		elif re.match(r"^>.+$", e.content[0].text):
+			includedDoc = convert_text(open(e.content[0].text[1:], "r").read(), standalone=True) # TODO: Put into function
+			oCommands = commands.copy()
+			oFlags = flags[:]
+			includedDoc = includedDoc.walk(transform)
+			commands = oCommands
+			flags = oFlags
+			#e = Div(*includedDoc.content)
+		
+		## Handle import [#path/file.md]{} TODO: implement properly as commands
+		# This is the exact opposite of include. We take the commands
+		# and flags but drop the content.
+		elif re.match(r"^#.+$", e.content[0].text):
+			importedDoc = convert_text(open(e.content[0].text[1:], "r").read(), standalone=True) # TODO: Put into function
+			importedDoc.walk(transform)
+			return nullify(e)
+
+	## Execute commands
 	# Walk transforms the children first, then the root element,
 	# so the content of the element the command receives is
 	# already transformed.
@@ -110,7 +135,8 @@ def transform(e: Element, doc: Doc) -> Element: # Returns next sibling element t
 	return e
 
 
-doc = convert_text(open(sys.argv[1], "r").read(), standalone=True, extra_args=["-f", "markdown+fenced_code_attributes"])
+doc = convert_text(open(sys.argv[1], "r").read(), standalone=True) # TODO: Put into function so we can specify extensions and parameters globally.
+
 
 print(show(doc))
 doc = doc.walk(transform)
diff --git a/test-import.md b/test-import.md
new file mode 100644
index 0000000..50b67c3
--- /dev/null
+++ b/test-import.md
@@ -0,0 +1,7 @@
+``` {.python define=nop}
+appendChildren(element.content)
+```
+
+``` {.python define=opendatatask}
+print("Toto je praktická open-data úloha. V [odevzdávátku](https://ksp.mff.cuni.cz/h/odevzdavatko/) si necháte vygenerovat vstupy a odevzdáte příslušné výstupy. Záleží jen na vás, jak výstupy vyrobíte.")
+```
diff --git a/test-include.md b/test-include.md
new file mode 100644
index 0000000..d4f3c09
--- /dev/null
+++ b/test-include.md
@@ -0,0 +1,14 @@
+I am a little piece of content
+
+# With a title!
+
+And things...
+
+``` {.python .run}
+# I set my own flags!
+flags.append("cat")
+```
+
+:::{if=cat}
+This should be only shown to included cats.
+:::
diff --git a/test.md b/test.md
index ba43a5f..ac89762 100644
--- a/test.md
+++ b/test.md
@@ -1,15 +1,14 @@
-``` {.python define=nop}
-appendChildren(element.content)
-```
-
-``` {.python define=opendatatask}
-print("Toto je praktická open-data úloha. V [odevzdávátku](https://ksp.mff.cuni.cz/h/odevzdavatko/) si necháte vygenerovat vstupy a odevzdáte příslušné výstupy. Záleží jen na vás, jak výstupy vyrobíte.")
-```
+---
+title: 'Wooooo a title'
+---
+[#test-import.md]{}
 
 # Hello world!
 
 This is an *example* **yay**!
 
+[>test-include.md]{}
+
 :::{if=cat}
 This should only be shown to cats
 :::
diff --git a/util.py b/util.py
index bf8540a..190aaca 100644
--- a/util.py
+++ b/util.py
@@ -1,4 +1,4 @@
-from panflute import Element, Block, Inline
+from panflute import Element, Block, Inline, Null, Str
 import re
 
 def replaceEl(e: Element, r: Element) -> Element:
@@ -8,3 +8,9 @@ def replaceEl(e: Element, r: Element) -> Element:
 	return r
 def deleteEl(e: Element):
 	del e.parent.content[e.index]
+
+def nullify(e: Element):
+	if isinstance(e, Inline):
+		return Str("")
+	elif isinstance(e, Block):
+		return Null()