Snap Packages This section describes the filesystem layout for snappy packages. Concepts Each snappy package is installed into its own directory. snappy packages will never overwrite files that belong to different packages or older versions of the same package. A normal snappy package can only read its own space and write to a special writable area. This is enforced via the apparmor profile for ubuntu-core apps. Structure Applications are installed to the /apps directory. Note that since applications are system-specific, they are ultimately stored on the /writable partition. The directories for a snap application are: Directory Writable? Description /apps/// No Read-only files, libraries, resource files, and other binary data shipped with the app. Exported as SNAPP_APP_PATH /var/lib/apps/// Yes Writable files, configuration or other data that is not specific to any user. This directory needs to be created by the application right now and will be created by the snappy tool soon. Exported as SNAPP_APP_DATA_PATH /var/lib/apps// No Read-only for the apps, backup purpose. /home/user/apps/// Yes Writable, configuration or other data specific to the calling user. The app needs to create them right now. They will be created by the snappy tool soon. Exported as SNAPP_USER_DATA_PATH /home/user/apps/// No Read-only for the configuration or other specific data for the calling user, backup purpose. This is not created by snappy right now but will be soon. /tmp/snapps///tmp Yes Writable temp location Exported as SNAPP_APP_TMPDIR, TMPDIR The directories in the table above will be created soon by the “snappy” command on install or upgrade. Right now the app needs to create them. In addition, these permissions will be enforced using AppArmor rules that are dynamically created on app install.