AttribBits

Opening the file without either the SSH_FXF_ACCESS_APPEND_DATA or the SSH_FXF_ACCESS_APPEND_DATA_ATOMIC flag (see section 8.1.1.3 of the SFTP standard draft) MUST result in an SSH_FX_INVALID_PARAMETER error.

The file should be included in backup / archive operations.

This attribute applies only to directories. This attribute is always read-only, and cannot be modified. This attribute means that files and directory names in this directory should be compared without regard to case.

It is recommended that where possible, the server's filesystem be allowed to do comparisons. For example, if a client wished to prompt a user before overwriting a file, it should not compare the new name with the previously retrieved list of names in the directory. Rather, it should first try to create the new file by specifying SSH_FXF_CREATE_NEW flag. Then, if this fails and returns SSH_FX_FILE_ALREADY_EXISTS, it should prompt the user and then retry the create specifying SSH_FXF_CREATE_TRUNCATE.

Unless otherwise specified, filenames are assumed to be case sensitive.

The file is stored on disk using file-system level transparent compression. This flag does not affect the file data on the wire.

The file is stored on disk using file-system level transparent encryption. This flag does not affect the file data on the wire (for either READ or WRITE requests.)

File SHOULD NOT be shown to user unless specifically requested. For example, most UNIX systems SHOULD set this bit if the filename begins with a 'period'. This bit may be read-only (see section 5.4 of the SFTP standard draft). Most UNIX systems will not allow this to be changed.

The file cannot be deleted or renamed, no hard link can be created to this file, and no data can be written to the file.

This bit implies a stronger level of protection than SSH_FILEXFER_ATTR_FLAGS_READONLY, the file permission mask or ACLs. Typically even the superuser cannot write to immutable files, and only the superuser can set or remove the bit.

Advisory, read-only bit. This bit is not part of the access control information on the file, but is rather an advisory field indicating that the file should not be written.

The file is a sparse file; this means that file blocks that have not been explicitly written are not stored on disk. For example, if a client writes a buffer at 10 M from the beginning of the file, the blocks between the previous EOF marker and the 10 M offset would not consume physical disk space.

Some servers may store all files as sparse files, in which case this bit will be unconditionally set. Other servers may not have a mechanism for determining if the file is sparse, and so the file MAY be stored sparse even if this flag is not set.

When the file is modified, the changes are written synchronously to the disk.

The file is part of the operating system.

The server MAY include this bit in a directory listing or realpath response. It indicates there was a failure in the translation to UTF-8. If this flag is included, the server SHOULD also include the UNTRANSLATED_NAME attribute.