Update cheatsheets

tldr/cisco-ios/interface

@@ -0,0 +1,18 @@
+---
+syntax: markdown
+tags: [tldr, cisco-ios]
+source: https://github.com/tldr-pages/tldr.git
+---
+# interface
+
+> Manage interfaces.
+> Accessed in configuration mode.
+> More information: <https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/interface/command/ir-cr-book/ir-i1.html>.
+
+- Configure a VLAN:
+
+`interface vlan {{1}}`
+
+- Set an interface to be active or inactive (this is run inside the interface command):
+
+`{{no shutdown|shutdown}}`