Merge pull request #8944 from aabadie/pr/examples/filesystem

examples/filesystem: fix typos and cleanup

examples/filesystem/README.md

 # File system usage example
 
-This is a basic example how to use a file system with RIOT in your embedded application.
+## Description
 
-This example shows:
- - how to mount/format/unmount a filesystem, with spiffs, littlefs and constfs examples
- - how to open/read/write/close a file with and without newlib
+This basic example shows how to use a file system with RIOT in your embedded
+application.
 
-In RIOT, most filesystems use `mtd` as flash interface. So to use this example
-you must define `MTD_0`. `MTD_0` is a pointer to a `mtd_dev_t` instance.
-This example use `littlefs` as default filesystem on the whole `mtd` device.
-A `constfs` filesystem is also demonstrated with two files.
+In particular, this example shows:
 
-All the RIOT filesystems are used through the `vfs` interface, and on most platform
-they can be accessed transparently with `open/close/read/write/...` functions.
+- how to mount/format/unmount a file system, either with spiffs, littlefs or
+  constfs
+- how to open/read/write/close a file with and without newlib
+
+In RIOT, most file systems use a `mtd` as flash interface. So to use this
+example one must define `MTD_0`. `MTD_0` is a pointer to a `mtd_dev_t`
+instance.
+
+This example uses `littlefs` as default file system on the whole `mtd`.
+A `constfs` file system is also demonstrated with two files.
+
+All the RIOT file systems are used through the `vfs` interface, and on most
+platforms files can be accessed transparently with `open/close/read/write/...`
+functions.
 With newlib, `fopen/fclose/fread/fwrite/...` can also be used transparently.
 
+## Shell commands
+
 The following commands are available:
- - `format`: should be called the first time only, it will format the `mtd` device
-with the comfigured filesystem
- - `mount`: mount the filesystem on the configured mount point (default is `/sda`
-but it can be configured with `FLASH_MOUNT_POINT` define). The `constfs` filesystem
-is mounted automatically when the application starts
- - `umount`: unmount `/sda`
- - `cat <file>`: similarly to unix `cat` unix command, it prints the given `<file>` on
-stdout
- - `tee <file> <str>`: similarly to `tee` unix command, it writes `<str>` in `<file>`
-
-Apart from these commands, the default `vfs` commands can be used, for instance:
- - `vfs df`: shows all mountpoints and used/available memory
- - `vfs ls <path>`: list files
+
+- `format`: should be called the first time only, it will format the `mtd`
+  with the configured file system
+- `mount`: mount the file system on the configured mount point (default is
+  `/sda` but it can be configured with `FLASH_MOUNT_POINT` define). The
+  `constfs` file system is mounted automatically on `/const` when the
+   application starts
+- `umount`: unmount `/sda`
+- `cat <file>`: similarly to unix `cat` unix command, it prints the given
+  `<file>` on stdout
+- `tee <file> <str>`: similarly to `tee` unix command, it writes `<str>` in
+  `<file>`
+
+Besides of these commands, the default `vfs` commands can be used, for
+instance:
+
+- `vfs df`: shows all mountpoints and used/available file system space
+- `vfs ls <path>`: list files
+
+## Example on `native` with `constfs`
+
+- Build and run the `filesystem` example application on the `native` target:
+
+```
+make -C examples/filesystem all term
+[...]
+main(): This is RIOT! (Version: 2018.04-devel-/examples/filesystem)
+constfs mounted successfully
+```
+
+- List the available files in the `constfs` predefined partition:
+
+```
+> ls /const
+ls /const
+/hello-world
+/hello-riot
+total 2 files
+```
+
+- Print the content of the files:
+
+```
+> cat /const/hello-world
+cat /const/hello-world
+Hello World!
+> cat /const/hello-riot
+cat /const/hello-riot
+Hello RIOT!
+```

examples/filesystem/main.c

@@ -103,7 +103,7 @@ static constfs_t constfs_desc = {
 };
 
 /* constfs mount point, as for previous example, it needs a file system driver,
- * a mount poinr and private_data is a pointer to the constfs descriptor */
+ * a mount point and private_data as a pointer to the constfs descriptor */
 static vfs_mount_t const_mount = {
     .fs = &constfs_file_system,
     .mount_point = "/const",