output

unix 下的C开发手册,还用详细的例程。

If
<
<i>
owner
name
</i>
&gt;
or
&lt;
<i>
group
name
</i>
&gt;
cannot
be
determined,
or
if
<b>
-n
</b>
is
given,
they
are
replaced
with
their
associated
numeric
values
using
the
format
%u.
<p>
The
&lt;
<i>
date
and
time
</i>
&gt;,
field
will
contain
the
appropriate
date
and
timestamp
of
when
the
file
was
last
modified.
In
the
POSIX
locale,
the
field
is
the
equivalent
of
the
output
of
the
following
<i>

<a href="date.html">
date
</a>

</i>
command:
<pre>
<code>
date "+%b %e %H:%M"
</code>
</pre>
if
the
file
has
been
modified
in
the
last
six
months,
or:
<pre>
<code>
date "+%b %e  %Y"
</code>
</pre>
(where
two
space
characters
are
used
between
<b>
%e
</b>
and
<b>
%Y)
</b>
if
the
file
has
not
been
modified
in
the
last
six
months
or
if
the
modification
date
is
in
the
future,
except
that,
in
both
cases,
the
final
newline
character
produced
by
<i>

<a href="date.html">
date
</a>

</i>
is
not
included
and
the
output
is
as
if
the
<i>

<a href="date.html">
date
</a>

</i>
command
were
executed
at
the
time
of
the
last
modification
date
of
the
file
rather
than
the
current
time.
When
the
LC_TIME
locale
category
is
not
set
to
the
POSIX
locale,
a
different
format
and
order
of
presentation
of
this
field
may
be
used.
<p>
If
the
file
is
a
character
special
or
block
special
file,
the
size
of
the
file
may
be
replaced
with
implementation-dependent
information
associated
with
the
device
in
question.
<p>
If
the
pathname
was
specified
as
a
<i>
file
</i>
operand,
it
will
be
written
as
specified.
<p>
The
file
mode
written
under
the
<b>
-l
</b>,
<b>
-g
</b>,
<b>
-n
</b>
and
<b>
-o
</b>
options
consists
of
the
following
format:
<p>

<code>
<pre>
<tt>"%c%s%s%s%c"</tt>, &lt;<i>entry&nbsp;type</i>&gt;,
&lt;<i>owner&nbsp;permissions</i>&gt;,
&lt;<i>group&nbsp;permissions</i>&gt;,
&lt;<i>other&nbsp;permissions</i>&gt;,
&lt;<i>optional&nbsp;alternate&nbsp;access&nbsp;method&nbsp;flag</i>&gt;
</pre>
</code>
<p>
The
&lt;
<i>
optional
alternate
access
method
flag
</i>
&gt;
is
a
single
space
character
if
there
is
no
alternate
or
additional
access
control
method
associated
with
the
file;
otherwise,
a
printable
character
is
used.
<p>
The
&lt;
<i>
entry
type
</i>
&gt;
character
describes
the
type
of
file,
as
follows:
<dl compact>
<dt>
d
<dd>
Directory.
<dt>
b
<dd>
Block
special
file.
<dt>
c
<dd>
Character
special
file.
<dt>
p
<dd>
FIFO.
<dt>
-
<dd>
Regular
file.
</dl>
<p>
Implementations
may
add
other
characters
to
this
list
to
represent
other,
implementation-dependent,
file
types.
<p>
The
next
three
fields
are
three
characters
each:
<dl compact>
<dt>
&lt;
<i>
owner
permissions
</i>
&gt;
<dd>
<font color=green size=-2>deleted text:</font><strike>



<br>



</strike>
Permissions
for
the
file
owner
class
(see
<b>
file
access
permissions
</b>
in
the
<b>
XBD
</b>
specification,
<a href="../xbd/glossary.html">

<b>
Glossary
</b>
&nbsp;
</a>
).
<dt>
&lt;
<i>
group
permissions
</i>
&gt;
<dd>
<font color=green size=-2>deleted text:</font><strike>



<br>



</strike>
Permissions
for
the
file
group
class.
<dt>
&lt;
<i>
other
permissions
</i>
&gt;
<dd>
<font color=green size=-2>deleted text:</font><strike>



<br>



</strike>
Permissions
for
the
file
other
class.
</dl>
<p>
Each
field
has
three
character
positions:
<ol>
<p>
<li>
If
r,
the
file
is
readable;
if
"-",
it
is
not
readable.
<p>
<li>
If
w,
the
file
is
writable;
if
"-",
it
is
not
writable.
<p>
<li>
The
first
of
the
following
that
applies:
<dl compact>
<dt>

<b>
S
</b>

<dd>
If
in
&lt;
<i>
owner
permissions
</i>
&gt;,
the
file
is
not
executable
and
set-user-ID
mode
is
set.
If
in
&lt;
<i>
group
permissions
</i>
&gt;,
the
file
is
not
executable
and
set-group-ID
mode
is
set.
<dt>

<b>
s
</b>

<dd>
If
in
&lt;
<i>
owner
permissions
</i>
&gt;,
the
file
is
executable
and
set-user-ID
mode
is
set.
If
in
&lt;
<i>
group
permissions
</i>
&gt;,
the
file
is
executable
and
set-group-ID
mode
is
set.
<dt>

<b>
x
</b>

<dd>
The
file
is
executable
or
the
directory
is
searchable.
<dt>

<b>
-
</b>

<dd>
None
of
the
attributes
of
S,
s
or
x
applies.
</dl>
<p>
Implementations
may
add
other
characters
to
this
list
for
the
third
character
position.
Such
additions
will,
however,
be
written
in
lower-case
if
the
file
is
executable
or
searchable,
and
in
upper-case
if
it
is
not.
<p>
</ol>
<p>
If
any
of
the
<b>
-l
</b>,
<b>
-g
</b>,
<b>
-n
</b>,
<b>
-o
</b>
or
<b>
-s
</b>
options
is
specified,
each
list
of
files
within
the
directory
will
be
preceded
by
a
status
line
indicating
the
number
of
file
system
blocks
occupied
by
files
in
the
directory
in
512-byte
units,
rounded
up
to
the
next
integral
number
of
units,
if
necessary.
In
the
POSIX
locale,
the
format
is:
<p>

<code>
<pre>
<tt>"total %u\n"</tt>, &lt;<i>number of units in the directory</i>&gt;
</pre>
</code>
<p>
If
more
than
one
directory,
or
a
combination
of
non-directory
files
and
directories
are
written,
either
as
a
result
of
specifying
multiple
operands,
or
the
<b>
-R
</b>
option,
each
list
of
files
within
a
directory
will
be
preceded
by:
<p>

<code>
<tt>
"\n%s:\n"
</tt>,
&lt;
<i>
directory
name
</i>
&gt;
</code>
<p>
If
this
string
is
the
first
thing
to
be
written,
the
first
newline
character
is
not
written.
This
output
precedes
the
number
of
units
in
the
directory.
<p>
If
the
<b>
-s
</b>
option
is
given,
each
file
shall
be
written
with
the
number
of
blocks
used
by
the
file.
Along
with
<b>
-C
</b>,
<b>
-1
</b>,
<b>
-m
</b>
or
<b>
-x
</b>,
the
number
and
a
space
character
precede
the
filename;
with
<b>
-g
</b>,
<b>
-l
</b>,
<b>
-n
</b>
or
<b>
-o
</b>,
they
precede
each
line
describing
a
file.
</blockquote><h4><a name = "tag_001_014_1299">&nbsp;</a>STDERR</h4><blockquote>
Used
only
for
diagnostic
messages.
</blockquote><h4><a name = "tag_001_014_1300">&nbsp;</a>OUTPUT FILES</h4><blockquote>
None.
</blockquote><h4><a name = "tag_001_014_1301">&nbsp;</a>EXTENDED DESCRIPTION</h4><blockquote>
None.
</blockquote><h4><a name = "tag_001_014_1302">&nbsp;</a>EXIT STATUS</h4><blockquote>
The
following
exit
values
are
returned:
<dl compact>
<dt>
0
<dd>
All
files
were
written
successfully.
<dt>
&gt;0
<dd>
An
error
occurred.
</dl>
</blockquote><h4><a name = "tag_001_014_1303">&nbsp;</a>CONSEQUENCES OF ERRORS</h4><blockquote>
Default.
</blockquote><h4><a name = "tag_001_014_1304">&nbsp;</a>APPLICATION USAGE</h4><blockquote>
Many
implementations
use
the
equal
sign
(=)
and
the
at
sign
(@)
to
denote
sockets
bound
to
the
file
system
and
symbolic
links,
respectively,
for
the
<b>
-F
</b>
option.
Similarly,
many
historical
implementations
use
the
s
character
and
the
l
character
to
denote
sockets
and
symbolic
links,
respectively,
as
the
entry
type
characters
for
the
<b>
-l
</b>
option.
<p>
It
is
difficult
for
an
application
to
use
every
part
of
the
file
modes
field
of
<i>
ls
</i>
<b>
-l
</b>
in
a
portable
manner.
Certain
file
types
and
executable
bits
are
not
guaranteed
to
be
exactly
as
shown,
as
implementations
may
have
extensions.
Applications
can
use
this
field
to
pass
directly
to
a
user
printout
or
prompt,
but
actions
based
on
its
contents
should
generally
be
deferred,
instead,
to
the
<i>

<a href="test.html">
test
</a>

</i>
utility.
<p>
The
output
of
<i>
ls
</i>
(with
the
<b>
-l
</b>
and
related
options)
contains
information
that
logically
could
be
used
by
utilities
such
as
<i>

<a href="chmod.html">
chmod
</a>

</i>
and
<i>

<a href="touch.html">
touch
</a>

</i>
to
restore
files
to
a
known
state.
However,
this
information
is
presented
in
a
format
that
cannot
be
used
directly
by
those
utilities
or
be
easily
translated
into
a
format
that
can
be
used.
A
character
has
been
added
to
the
end
of
the
permissions
string
so
that
applications
will
at
least
have
an
indication
that
they
may
be
working
in
an
area
they
do
not
understand
instead
of
assuming
that
they
can
translate
the
permissions
string
into
something
that
can
be
used.
Future
issues
or
related
documents
may
define
one
or
more
specific
characters
to
be
used
based
on
different
standard
additional
or
alternative
access
control
mechanisms.
<p>
As
with
many
of
the
utilities
that
deal
with
filenames,
the
output
of
<i>
ls
</i>
for
multiple
files
or
in
one
of
the
long
listing
formats
must
be
used
carefully
on
systems
where
filenames
can
contain
embedded
white
space.
Systems
and
system
administrators
should
institute
policies
and
user
training
to
limit
the
use
of
such
filenames.
<p>
The
number
of
disk
blocks
occupied
by
the
file
that
it
reports
varies
depending
on
underlying
file
system
type,
block
size
units
reported
and
the
method
of
calculating
the
number
of
blocks.
On
some
file
system
types,
the
number
is
the
actual
number
of
blocks
occupied
by
the
file
(counting
indirect
blocks
and
ignoring
holes
in
the
file);
on
others
it
is
calculated
based
on
the
file
size
(usually
making
an
allowance
for
indirect
blocks,
but
ignoring
holes).
</blockquote><h4><a name = "tag_001_014_1305">&nbsp;</a>EXAMPLES</h4><blockquote>
An
example
of
a
small
directory
tree
being
fully
listed
with
<i>
ls
</i>
<b>
-laRF
</b>
<b>
a
</b>
in
the
POSIX
locale:
<pre>
<code>
total 11
drwxr-xr-x   3 hlj      prog          64 Jul  4 12:07 ./
drwxrwxrwx   4 hlj      prog        3264 Jul  4 12:09 ../
drwxr-xr-x   2 hlj      prog          48 Jul  4 12:07 b/
-rwxr--r--   1 hlj      prog         572 Jul  4 12:07 foo*

a/b:
total 4
drwxr-xr-x   2 hlj      prog          48 Jul  4 12:07 ./
drwxr-xr-x   3 hlj      prog          64 Jul  4 12:07 ../
-rw-r--r--   1 hlj      prog         700 Jul  4 12:07 bar
</code>
</pre>
</blockquote><h4><a name = "tag_001_014_1306">&nbsp;</a>FUTURE DIRECTIONS</h4><blockquote>
The
<b>
-s
</b>
uses
implementation-dependent
units
and
cannot
be
used
portably;
it
may
be
withdrawn
in
a
future
issue.
<p>
The
IEEE
PASC
1003.2
Interpretations
Committee
has
forwarded
concerns
about
parts
of
this
interface
definition
to
the
IEEE
PASC
Shell
and
Utilities
Working
Group
which
is
identifying
the
corrections.
A
future
revision
of
this
specification
will
align
with
IEEE
Std.
1003.2b
when
finalised.
</blockquote><h4><a name = "tag_001_014_1307">&nbsp;</a>SEE ALSO</h4><blockquote>
<i>

<a href="chmod.html">
chmod
</a>

</i>,
<i>

<a href="find.html">
find
</a>

</i>,
the
<b>
XSH
</b>
specification
description
of
<i>

<a href="../xsh/sysstat.h.html">
&lt;sys/stat.h&gt;
</a>

</i>.
</blockquote>

<hr size=2 noshade>
<center>

<font size=2>
UNIX
&reg;
is
a
registered
Trademark
of
The
Open
Group.
<br>
Copyright
&copy;
1997
The
Open
Group
<br>
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