Use this tag if your issue is with permissions in the file system (files & directories). For app permissions, use the 'permissions' tag instead.
What are file permissions?
Android uses Linux at its core, and Unix/Linux use a special permission system on files:
- each file has an owner (single user), and a group (user group) it is owned by
- permissions are granted to the owner, the group, and "others" (neither being the user nor belonging to the group)
- permissions basically consist of being allowed to read, write, and execute a file (in case of a directory, "execute" means to change into it)
Thus a permission-set basically consists of three groups, prefixed by a "type":
drwxrwxrwxwould be a directory with full permissions to everybody
-rwx------would be a very private file (only the owner has permissions to do everything with it)
-rw-rw---looks like a document/data file read- and writable by the owner and the group.