permissions
public static int permissions(java.io.File f)
Get file permissions in octal mode, e.g. 0755.
Note: it uses `java.nio.file.attribute.PosixFilePermission` if OS supports this, otherwise reverts to
using standard Java file operations, e.g. `java.io.File#canExecute()`. In the first case permissions will
be precisely as reported by the OS, in the second case 'owner' and 'group' will have equal permissions and
'others' will have no permissions, e.g. if file on Windows OS is `read-only` permissions will be `0550`.
- Throws:
java.lang.NullPointerException
- if file is null.
java.lang.IllegalArgumentException
- if file does not exist.