<s>
File	B-Application
attributes	I-Application
are	O
a	O
type	O
of	O
meta-data	O
that	O
describe	O
and	O
may	O
modify	O
how	O
files	B-Operating_System
and/or	O
directories	B-Application
in	O
a	O
filesystem	B-Application
behave	O
.	O
</s>
<s>
Typical	O
file	B-Application
attributes	I-Application
may	O
,	O
for	O
example	O
,	O
indicate	O
or	O
specify	O
whether	O
a	O
file	B-Operating_System
is	O
visible	O
,	O
modifiable	O
,	O
compressed	O
,	O
or	O
encrypted	O
.	O
</s>
<s>
Attributes	O
are	O
considered	O
distinct	O
from	O
other	O
metadata	O
,	O
such	O
as	O
dates	O
and	O
times	O
,	O
filename	O
extensions	O
or	O
file	B-Application
system	I-Application
permissions	O
.	O
</s>
<s>
In	O
addition	O
to	O
files	B-Operating_System
,	O
folders	O
,	O
volumes	O
and	O
other	O
file	B-Application
system	I-Application
objects	O
may	O
have	O
attributes	O
.	O
</s>
<s>
Traditionally	O
,	O
in	O
DOS	B-Device
and	O
Microsoft	B-Application
Windows	I-Application
,	O
files	B-Operating_System
and	O
folders	O
accepted	O
four	O
attributes	O
:	O
</s>
<s>
Archive	O
(	O
A	O
)	O
:	O
When	O
set	O
,	O
it	O
indicates	O
that	O
the	O
hosting	O
file	B-Operating_System
has	O
changed	O
since	O
the	O
last	O
backup	B-Protocol
operation	O
.	O
</s>
<s>
Windows	O
 '	O
file	B-Application
system	I-Application
sets	O
this	O
attribute	O
on	O
any	O
file	B-Operating_System
that	O
has	O
changed	O
.	O
</s>
<s>
Backup	B-Protocol
software	O
then	O
has	O
the	O
duty	O
of	O
clearing	O
it	O
upon	O
a	O
successful	O
full	O
or	O
incremental	O
backup	B-Protocol
(	O
not	O
a	O
differential	O
one	O
)	O
.	O
</s>
<s>
Hidden	O
(	O
H	O
)	O
:	O
When	O
set	O
,	O
indicates	O
that	O
the	O
hosting	O
file	B-Operating_System
is	O
hidden	O
.	O
</s>
<s>
MS-DOS	O
commands	O
like	O
dir	B-Application
and	O
Windows	O
apps	O
like	O
File	B-Protocol
Explorer	I-Protocol
do	O
not	O
show	O
hidden	B-Application
files	I-Application
by	O
default	O
,	O
unless	O
asked	O
to	O
do	O
so	O
.	O
</s>
<s>
System	O
(	O
S	O
)	O
:	O
When	O
set	O
,	O
indicates	O
that	O
the	O
hosting	O
file	B-Operating_System
is	O
a	O
critical	O
system	O
file	B-Operating_System
that	O
is	O
necessary	O
for	O
the	O
computer	O
to	O
operate	O
properly	O
.	O
</s>
<s>
MS-DOS	O
and	O
Microsoft	B-Application
Windows	I-Application
use	O
it	O
to	O
mark	O
important	O
system	O
files	B-Operating_System
.	O
</s>
<s>
MS-DOS	O
commands	O
like	O
dir	B-Application
and	O
Windows	O
apps	O
like	O
File	B-Protocol
Explorer	I-Protocol
do	O
not	O
show	O
system	O
files	B-Operating_System
by	O
default	O
even	O
when	O
hidden	B-Application
files	I-Application
are	O
shown	O
,	O
unless	O
asked	O
to	O
do	O
so	O
.	O
</s>
<s>
Read-only	O
(	O
R	O
)	O
:	O
When	O
set	O
,	O
indicates	O
that	O
a	O
file	B-Operating_System
should	O
not	O
be	O
altered	O
.	O
</s>
<s>
Upon	O
opening	O
the	O
file	B-Operating_System
,	O
file	B-Application
system	I-Application
API	B-General_Concept
usually	O
does	O
not	O
grant	O
write	O
permission	O
to	O
the	O
requesting	O
application	O
,	O
unless	O
the	O
application	O
explicitly	O
requests	O
it	O
.	O
</s>
<s>
As	O
new	O
versions	O
of	O
Windows	O
came	O
out	O
,	O
Microsoft	O
has	O
added	O
to	O
the	O
inventory	O
of	O
available	O
attributes	O
on	O
the	O
NTFS	B-Application
file	I-Application
system	I-Application
,	O
including	O
but	O
not	O
limited	O
to	O
:	O
</s>
<s>
Compressed	O
(	O
C	O
)	O
:	O
When	O
set	O
,	O
Windows	O
compresses	B-General_Concept
the	O
hosting	O
file	B-Operating_System
upon	O
storage	O
.	O
</s>
<s>
Encrypted	O
(	O
E	O
)	O
:	O
When	O
set	O
,	O
Windows	O
encrypts	B-Application
the	O
hosting	O
file	B-Operating_System
upon	O
storage	O
to	O
prevent	O
unauthorized	O
access	O
.	O
</s>
<s>
Not	O
Content-Indexed	O
(	O
I	O
)	O
:	O
When	O
set	O
,	O
Indexing	B-Library
Service	I-Library
or	O
Windows	B-Application
Search	I-Application
do	O
not	O
include	O
the	O
hosting	O
file	B-Operating_System
in	O
their	O
indexing	O
operation	O
.	O
</s>
<s>
Other	O
attributes	O
that	O
are	O
displayed	O
in	O
the	O
"	O
Attributes	O
"	O
column	O
of	O
Windows	B-Protocol
Explorer	I-Protocol
include	O
:	O
</s>
<s>
Directory	B-Application
(	O
D	O
)	O
:	O
The	O
entry	O
is	O
a	O
subdirectory	B-Application
,	O
containing	O
file	B-Operating_System
and	O
directory	B-Application
entries	O
of	O
its	O
own	O
.	O
</s>
<s>
Reparse	O
Point	O
(	O
L	O
)	O
:	O
The	O
file	B-Operating_System
or	O
directory	B-Application
has	O
an	O
associated	O
re-parse	O
point	O
,	O
or	O
is	O
a	O
symbolic	B-Application
link	I-Application
.	O
</s>
<s>
Offline	O
(	O
O	O
)	O
:	O
The	O
file	B-Operating_System
data	O
is	O
physically	O
moved	O
to	O
offline	O
storage	O
(	O
Remote	O
Storage	O
)	O
.	O
</s>
<s>
Sparse	O
(	O
P	O
)	O
:	O
The	O
file	B-Operating_System
is	O
a	O
sparse	B-General_Concept
file	I-General_Concept
,	O
i.e.	O
,	O
its	O
contents	O
are	O
partially	O
empty	O
and	O
non-contiguous	O
.	O
</s>
<s>
Temporary	O
(	O
T	O
)	O
:	O
The	O
file	B-Operating_System
is	O
used	O
for	O
temporary	O
storage	O
.	O
</s>
<s>
In	O
DOS	B-Device
,	O
OS/2	B-Application
and	O
Windows	O
,	O
the	O
attrib	O
command	O
in	O
cmd.exe	B-Device
and	O
command.com	B-Operating_System
can	O
be	O
used	O
to	O
change	O
and	O
display	O
the	O
four	O
traditional	O
file	B-Application
attributes	I-Application
.	O
</s>
<s>
File	B-Protocol
Explorer	I-Protocol
in	O
Windows	O
can	O
show	O
the	O
seven	O
mentioned	O
attributes	O
but	O
cannot	O
set	O
or	O
clear	O
the	O
System	O
attribute	O
.	O
</s>
<s>
Windows	B-Application
PowerShell	I-Application
,	O
which	O
has	O
become	O
a	O
component	O
of	O
Windows	B-Device
7	I-Device
and	O
later	O
,	O
features	O
two	O
commands	O
that	O
can	O
read	O
and	O
write	O
attributes	O
:	O
Get-ItemProperty	O
and	O
Set-ItemProperty	O
.	O
</s>
<s>
To	O
change	O
an	O
attribute	O
on	O
a	O
file	B-Operating_System
on	O
Windows	B-Device
NT	I-Device
,	O
the	O
user	O
must	O
have	O
appropriate	O
file	B-Application
system	I-Application
permissions	O
known	O
as	O
Write	O
Attributes	O
and	O
Write	O
Extended	B-Application
Attributes	I-Application
.	O
</s>
<s>
In	O
Unix	B-Application
and	O
Unix-like	O
systems	O
,	O
including	O
POSIX-conforming	O
systems	O
,	O
each	O
file	B-Operating_System
has	O
a	O
'	O
mode	O
 '	O
containing	O
9	O
bit	O
flags	O
controlling	O
read	O
,	O
write	O
and	O
execute	O
permission	O
for	O
each	O
of	O
the	O
file	B-Operating_System
's	O
owner	O
,	O
group	O
and	O
all	O
other	O
users	O
(	O
see	O
File-system	B-Application
permissions	O
§Traditional	O
Unix	B-Application
permissions	O
for	O
more	O
details	O
)	O
plus	O
the	O
setuid	O
and	O
setgid	O
bit	O
flags	O
and	O
a	O
'	B-Application
sticky	I-Application
 '	I-Application
bit	I-Application
flag	I-Application
.	O
</s>
<s>
The	O
mode	O
also	O
specifies	O
the	O
file	B-Application
type	I-Application
(	O
regular	O
file	B-Operating_System
,	O
directory	B-Application
,	O
or	O
some	O
other	O
special	O
kind	O
)	O
.	O
</s>
<s>
In	O
4.4BSD	O
and	O
4.4BSD-Lite	O
,	O
files	B-Operating_System
and	O
directories	B-Application
(	O
folders	O
)	O
accepted	O
four	O
attributes	O
that	O
could	O
be	O
set	O
by	O
the	O
owner	O
of	O
the	O
file	B-Operating_System
or	O
the	O
superuser	B-Application
(	O
the	O
"	O
User	O
"	O
attributes	O
)	O
and	O
two	O
attributes	O
that	O
could	O
only	O
be	O
set	O
by	O
the	O
superuser	B-Application
(	O
the	O
"	O
System	O
"	O
attributes	O
)	O
:	O
</s>
<s>
(	O
User	O
)	O
No-dump	O
:	O
When	O
set	O
,	O
it	O
indicates	O
that	O
the	O
file	B-Operating_System
or	O
directory	B-Application
should	O
not	O
be	O
saved	O
during	O
a	O
backup	B-Protocol
operation	O
.	O
</s>
<s>
(	O
User	O
and	O
System	O
)	O
Immutable	O
:	O
When	O
set	O
,	O
indicates	O
that	O
the	O
file	B-Operating_System
or	O
directory	B-Application
should	O
not	O
be	O
altered	O
.	O
</s>
<s>
Attempts	O
to	O
open	O
the	O
file	B-Operating_System
for	O
writing	O
,	O
create	O
a	O
file	B-Operating_System
within	O
the	O
directory	B-Application
,	O
remove	O
a	O
file	B-Operating_System
from	O
the	O
directory	B-Application
,	O
rename	O
a	O
file	B-Operating_System
within	O
the	O
directory	B-Application
,	O
rename	O
the	O
file	B-Operating_System
or	O
directory	B-Application
,	O
or	O
remove	O
the	O
file	B-Operating_System
or	O
directory	B-Application
will	O
fail	O
with	O
a	O
permissions	O
error	O
.	O
</s>
<s>
(	O
User	O
and	O
System	O
)	O
Append-only	O
:	O
When	O
set	O
,	O
indicates	O
that	O
the	O
file	B-Operating_System
should	O
only	O
be	O
appended	O
to	O
.	O
</s>
<s>
(	O
User	O
)	O
Opaque	O
:	O
When	O
set	O
on	O
a	O
directory	B-Application
,	O
indicates	O
that	O
the	O
directory	B-Application
is	O
opaque	O
when	O
viewed	O
through	O
a	O
union	B-Application
stack	I-Application
.	O
</s>
<s>
FreeBSD	B-Operating_System
added	O
some	O
additional	O
attributes	O
,	O
also	O
supported	O
by	O
DragonFly	B-Application
BSD	I-Application
:	O
</s>
<s>
(	O
User	O
and	O
System	O
)	O
No-unlink	O
:	O
When	O
set	O
,	O
indicates	O
that	O
the	O
file	B-Operating_System
or	O
directory	B-Application
should	O
not	O
be	O
renamed	O
or	O
removed	O
.	O
</s>
<s>
Attempts	O
to	O
rename	O
or	O
remove	O
the	O
file	B-Operating_System
or	O
directory	B-Application
will	O
fail	O
with	O
a	O
permissions	O
error	O
.	O
</s>
<s>
FreeBSD	B-Operating_System
also	O
supports	O
:	O
</s>
<s>
(	O
System	O
)	O
No-archive	O
:	O
When	O
set	O
,	O
indicates	O
that	O
the	O
file	B-Operating_System
or	O
directory	B-Application
should	O
not	O
be	O
archived	O
.	O
</s>
<s>
(	O
System	O
)	O
Snapshot	O
:	O
When	O
set	O
,	O
indicates	O
that	O
the	O
file	B-Operating_System
or	O
directory	B-Application
is	O
a	O
snapshot	O
file	B-Operating_System
.	O
</s>
<s>
This	O
attribute	O
is	O
maintained	O
by	O
the	O
system	O
,	O
and	O
cannot	O
be	O
set	O
,	O
even	O
by	O
the	O
super-user	B-Application
.	O
</s>
<s>
whereas	O
DragonFly	B-Application
BSD	I-Application
supports	O
:	O
</s>
<s>
(	O
User	O
and	O
System	O
)	O
No-history	O
:	O
When	O
set	O
,	O
indicates	O
that	O
history	O
should	O
not	O
be	O
retained	O
for	O
the	O
file	B-Operating_System
or	O
directory	B-Application
.	O
</s>
<s>
(	O
User	O
)	O
Swapcache	O
:	O
When	O
set	O
,	O
indicates	O
that	O
clean	O
filesystem	B-Application
data	O
for	O
the	O
file	B-Operating_System
,	O
or	O
for	O
the	O
directory	B-Application
and	O
everything	O
underneath	O
the	O
directory	B-Application
,	O
should	O
be	O
cached	O
in	O
swap	O
space	O
on	O
a	O
solid-state	B-Device
drive	I-Device
.	O
</s>
<s>
(	O
System	O
)	O
Swapcache	O
:	O
When	O
set	O
,	O
indicates	O
that	O
clean	O
filesystem	B-Application
data	O
for	O
the	O
file	B-Operating_System
,	O
or	O
for	O
the	O
directory	B-Application
and	O
everything	O
underneath	O
the	O
directory	B-Application
,	O
should	O
not	O
be	O
cached	O
in	O
swap	O
space	O
on	O
a	O
solid-state	B-Device
drive	I-Device
.	O
</s>
<s>
(	O
System	O
)	O
Archived	O
:	O
When	O
set	O
,	O
indicates	O
that	O
the	O
file	B-Operating_System
or	O
directory	B-Application
may	O
be	O
archived	O
.	O
</s>
<s>
NetBSD	B-Device
added	O
another	O
attribute	O
,	O
also	O
supported	O
by	O
OpenBSD	B-Operating_System
:	O
</s>
<s>
(	O
System	O
)	O
Archived	O
:	O
When	O
set	O
,	O
indicates	O
that	O
the	O
file	B-Operating_System
or	O
directory	B-Application
is	O
archived	O
.	O
</s>
<s>
macOS	B-Application
added	O
three	O
attributes	O
:	O
</s>
<s>
(	O
User	O
)	O
Hidden	O
:	O
When	O
set	O
,	O
indicates	O
that	O
the	O
file	B-Operating_System
or	O
directory	B-Application
should	O
not	O
,	O
by	O
default	O
,	O
be	O
displayed	O
in	O
the	O
GUI	O
;	O
ls	B-Application
will	O
display	O
it	O
,	O
however	O
.	O
</s>
<s>
In	O
these	O
systems	O
,	O
the	O
chflags	B-Device
and	O
ls	B-Application
commands	O
can	O
be	O
used	O
to	O
change	O
and	O
display	O
file	B-Application
attributes	I-Application
.	O
</s>
<s>
To	O
change	O
a	O
"	O
user	O
"	O
attribute	O
on	O
a	O
file	B-Operating_System
in	O
4.4BSD-derived	O
operating	O
systems	O
,	O
the	O
user	O
must	O
be	O
the	O
owner	O
of	O
the	O
file	B-Operating_System
or	O
the	O
superuser	B-Application
;	O
to	O
change	O
a	O
"	O
system	O
"	O
attribute	O
,	O
the	O
user	O
must	O
be	O
the	O
superuser	B-Application
.	O
</s>
<s>
The	O
Linux	B-Application
operating	I-Application
system	I-Application
can	O
support	O
a	O
wide	O
range	O
of	O
file	B-Application
attributes	I-Application
that	O
can	O
be	O
listed	O
by	O
the	O
lsattr	O
command	O
and	O
modified	O
,	O
where	O
possible	O
,	O
by	O
the	O
chattr	B-Device
command	O
.	O
</s>
<s>
Programs	O
can	O
examine	O
and	O
alter	O
attributes	O
using	O
ioctl	B-Operating_System
operations	O
.	O
</s>
<s>
Many	O
Linux	B-Application
file	B-Application
systems	I-Application
support	O
only	O
a	O
limited	O
set	O
of	O
attributes	O
,	O
and	O
none	O
of	O
them	O
support	O
every	O
attribute	O
that	O
chattr	B-Device
can	O
change	O
.	O
</s>
<s>
File	B-Application
systems	I-Application
that	O
support	O
at	O
least	O
some	O
attributes	O
include	O
ext4	B-Application
,	O
XFS	B-Application
and	O
btrfs	B-Operating_System
.	O
</s>
<s>
+	O
Common	O
file	B-Application
attributes	I-Application
supported	O
by	O
many	O
common	O
Linux	B-Application
file	B-Operating_System
systemsAttribute	O
flag	O
optionSemantics	O
and	O
rationaleNo	O
atime	O
updatesA+A	O
,	O
-A	O
record	O
is	O
not	O
modified	O
when	O
file	B-Operating_System
is	O
read/accessed.Append	O
-onlya	O
+a	O
,	O
-aWriting	O
to	O
file	B-Operating_System
only	O
allowed	O
in	O
append	O
mode.Immutablei	O
+i	O
,	O
-iPrevents	O
any	O
change	O
to	O
file	B-Operating_System
's	O
contents	O
or	O
metadata	O
:	O
file/directory	O
cannot	O
be	O
written	O
to	O
,	O
deleted	O
,	O
renamed	O
,	O
or	O
hard-linked.No	O
dumpd+d	O
,	O
-dFile	O
is	O
skipped	O
by	O
the	O
programSecure	O
deletions+s	O
,	O
-sRequests	O
that	O
,	O
when	O
deleted	O
,	O
all	O
file	B-Operating_System
data	O
blocks	O
are	O
filled	O
with	O
zeroes.Synchronous	O
updatesS+S	O
,	O
-SChanges	O
are	O
written	O
synchronously	O
to	O
the	O
underlying	O
filesystem	B-Application
storage	O
medium	O
;	O
equivalent	O
to	O
'	O
sync	O
 '	O
mount	O
option	O
for	O
affected	O
files	B-Operating_System
.	O
</s>
<s>
Support	O
for	O
"	O
system	O
attributes	O
"	O
(	O
in	O
which	O
the	O
operating	O
system	O
defines	O
the	O
meaning	O
,	O
unlike	O
general	O
extended	B-Application
file	I-Application
attributes	I-Application
)	O
was	O
added	O
to	O
OpenSolaris	O
in	O
2007	O
in	O
support	O
of	O
the	O
CIFS	O
server	O
.	O
</s>
<s>
It	O
has	O
been	O
carried	O
forward	O
from	O
there	O
into	O
both	O
the	O
Oracle	B-Application
Solaris	I-Application
11	O
releases	O
and	O
the	O
open	O
source	O
illumos	B-Application
project	O
.	O
</s>
<s>
In	O
this	O
implementation	O
,	O
a	O
can	O
be	O
set	O
via	O
the	O
chmod	B-Application
command	O
and	O
listed	O
by	O
the	O
ls	B-Application
command	O
.	O
</s>
<s>
Currently	O
the	O
ZFS	B-Application
file	B-Application
system	I-Application
supports	O
all	O
defined	O
attributes	O
,	O
and	O
starting	O
in	O
Oracle	B-Application
Solaris	I-Application
11.2	O
,	O
the	O
tmpfs	B-Application
file	B-Application
system	I-Application
supports	O
a	O
subset	O
of	O
attributes	O
.	O
</s>
<s>
+	O
Common	O
file	B-Application
attributes	I-Application
supported	O
by	O
Oracle	B-Application
Solaris	I-Application
and	O
illumos	B-Application
systemsAttributeCompact	O
flag	O
for	O
&	O
Semantics	O
and	O
rationaleappendonlyaWriting	O
to	O
file	B-Operating_System
only	O
allowed	O
in	O
append	O
mode.immutableiPrevents	O
any	O
change	O
to	O
file	B-Operating_System
's	O
contents	O
or	O
metadata	O
(	O
except	O
access	O
time	O
)	O
:	O
file/directory	O
cannot	O
be	O
written	O
to	O
,	O
deleted	O
,	O
or	O
renamed.nodumpdFile	O
should	O
be	O
skipped	O
by	O
backup	B-Protocol
programsnounlinkuPrevents	O
removing	O
the	O
file	B-Operating_System
,	O
but	O
allows	O
other	O
changes	O
.	O
</s>
