0x0001
Hidden file. When this attribute is set, the file should be omitted from default views in the user interface and from wildcard matches in user commands (e.g., "rm *"). On some systems, a naming convention is used to mark files as hidden, such as ".xxx" files on Unix; on other systems, there's formal file system metadata corresponding to this attribute, such as on Windows. Note that actually hiding files marked as hidden is up to the user interface; at a programmatic level, hidden files are treated the same as any other file, and in particular they're included in listDir() results. It's up to the caller to decide whether or not to filter hidden files out of listDir() results, and if so to do the filtering. The hidden attribute isn't enforced as a security or permissions mechanism in the file system; it doesn't prevent a user from explicitly viewing or deleting a file. It's merely designed as a convenience for the user, to reduce clutter in normal directory listings by filtering out system or application files (such as preference files, caches, or indices) that the user doesn't normally access directly.

0x0004
The file is readable by the current process. If this is set, it means that the program has the necessary ownership and access privileges to read the file. It's not guaranteed that a given attempt to read the file will actually succeed, since other conditions could arise, such as physical media errors or locking by another process that prevents concurrent access.

0x0002
System file. This is a file system attribute on some systems (notably Windows) that marks a file as belonging to or being part of the operating system. For practical purposes, system files should be treated the same as hidden files; the only reason we distinguish "system" as a separate attribute from "hidden" is to allow applications to display the two attributes separately when presenting file information to the user, who might expect to see both attributes on systems where both exist. There's no equivalent of this attribute on most systems other than DOS and Windows; it won't ever appear in a file's attributes on systems where there's no equivalent.

0x0008
The file is writable by the current process. If this is set, it means that the program has the necessary ownership and access privileges to write to the file. It's not guaranteed that a given attempt to write to the file will actually succeed, since other conditions could arise, such as insufficient disk space, physical media errors, or locking by another process that prevents concurrent access.

0x0008
block-mode device (e.g., Linux raw disk device)

0x0004
character-mode device (e.g., console)

0x0002
directory (folder)

0x0001
ordinary file (on disk or similar storage device)

0x0040
symbolic link (a filename that links to another file or directory)

0x0100
special system-defined parent directory link (such as Unix "..")

0x0010
pipe (sometimes called a FIFO) or similar interprocess channel

0x0080
special system-defined directory link to self (such as Unix ".")

0x0020
network socket