cmd: add page (#2345)

pages/windows/cmd.md

@@ -0,0 +1,35 @@
+# cmd
+
+> The Windows command interpreter.
+
+- Start a new instance of the command interpreter:
+
+`cmd`
+
+- Run the specified command and then exit:
+
+`cmd /c "{{command}}"`
+
+- Run the specified command and then enter an interactive shell:
+
+`cmd /k "{{command}}"`
+
+- Disable the usage of `echo` in command output:
+
+`cmd /q`
+
+- Enable or disable command extensions:
+
+`cmd /e:{{on|off}}`
+
+- Enable or disable file or directory autocompletion:
+
+`cmd /f:{{on|off}}`
+
+- Enable or disable environment variable expansion:
+
+`cmd /v:{{on|off}}`
+
+- Force output to use unicode encoding:
+
+`cmd /u`