RIOT/examples/filesystem

File system usage example

This is a basic example how to use a file system with RIOT in your embedded application.

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

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.

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. With newlib, fopen/fclose/fread/fwrite/... can also be used transparently.

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