写这个博客的目的是，给自己学透stat命令。也希望能帮助大家进一步了解此命令。详细介绍乃本人对manual的渣翻译，如有错，请指正。
一·Stat简要介绍：
1. stat函数以一个文件所在的路径为参数，返回此文件的结构
展示文件状态。
二·Stat详细介绍（DESCRIPTION）：
1. stat展示了被文件指向的文件的信息。
不要求被指定的文件有读，写或执行权限，但是在路径名内的所有目录必须是可搜索的<-意思是这目录必须可见或必须有？
如果没给定参数，stat会展示标准输入的file descriptor。
例如：
statcrw--w---- 1 Dala tty 268435456 0 "May 4 18:51:10 2017" "May 4 18:51:10 2017" "May 4 18:51:10 2017" "Jan 1 08:00:00 1970" 131072 0 0 (stdin)
用readlink调用时，只有软连接的目标文件被打印出来。如果给定的参数不是软链接，readlink会什么都不打印，因错误推、退出！
例如：
readlink 文件名当文件名不是一个软链接时，返回为空！
展示的信息是从用给定的参数调用lstat函数以及计算返回结构得到的。
三·使用选项：（不要嫌看它们烦，存在即合理！<-说给自己听的！）
-F
使用-F得到的结果，若后面为‘／’表明此路径名为一个目录；
‘*’表明这是可执行的；
‘@’表明这是一个软链接；
‘%’表明这是一个white-out（这里的white-out指什么？欢迎补充。）；
‘=’表明套接字；
‘|’表明这是一个先进先出。
示例：
stat -F ~/Documents
Documents为路径
结果：
drwx------ 15 dala staff 510 May 3 18:24:30 2017 /Users/dala/Documents/故documents后有‘／’
-f format
用一个指定的格式来显示信息，更多请看格式FORMATS部分（就在下一部分哦！）。
-L
使用stat而不是lstat。stat报告的信息会是文件的目标文件（如果这个文件是一个软链接的话），而不是这个文件本身！
-l
使用 ls -lT格式显示输出。
-n
不会空对每一个输出另外空起一行。
-q
如果stat或lstat命令失败能压制错误信息（就是不打印出错误信息啦！），但使用readlink时，万一错了，错误信息是不会打印的哦！
-r
显示出原始的，数字的信息。
示例：
使用前：
stat ~/Documents/结果
：
16777220 622483 drwx------ 15 data staff 0 510 "May 4 18:04:36 2017" "May 3 18:24:30 2017" "May 3 18:24:30 2017" "Jul 9 06:33:08 2015" 4096 0 0 /Users/dala/Documents/
使用后：
stat -r ~/Documents/
结果：
16777220 622483 040700 15 501 20 0 510 1493892276 1493807070 1493807070 1436394788 4096 0 0 /Users/dala/Documents/
-s
用shell output 的方式显示信息，适用于初始化变量。
示例：
stat -s ~/Documents/
结果：
st_dev=16777220 st_ino=622483 st_mode=040700 st_nlink=15 st_uid=501 st_gid=20 st_rdev=0 st_size=510 st_atime=1493892276 st_mtime=1493807070 st_ctime=1493807070 st_birthtime=1436394788 st_blksize=4096 st_blocks=0 st_flags=0
-t timefmt
用指定的格式来显示时间戳。
-x
用更啰嗦的方法来显示信息。
示例：
stat -x ~/Documents/
结果：
File: "/Users/dala/Documents/"
Size: 510 FileType: Directory
Mode: (0700/drwx------) Uid: ( 501/dala) Gid: ( 20/ staff)
Device: 1,4 Inode: 622483 Links: 15
Access: Thu May 4 18:04:36 2017
Modify: Wed May 3 18:24:30 2017
Change: Wed May 3 18:24:30 2017
四·格式 Formats
格式串与printf格式相似，在于他们开始与%，之后跟着格式的字符，以选择了stat结构体中被格式的字段（fields）的字符而结束。
%n表示另起一行；
%t表示tab；
%%表示百分比字符；
%@表示当前文件数量。
有以下可选择的表示标示:
#
为十进制与十六进制选择其他输出格式。非0的十进制输出前会有一个0，非0的十六进制数输出前会有0x。
+
使打印出来的数字带符号。
-
使向左对齐。
0
在左边填0而不是空白。
space
在负符号的数值前空一格，+覆盖space，如果+和space一起用的话。
有以下的字段：
size
一个表明的字段长度的可选用的十进制字符串。
prec
用例子解释 10.6，10表示字符串的最大长度，6表示小数点后的位数。
以下的有时间再翻译。
fmt An optional output format specifier
which is one of D, O, U, X, F, or S.
These represent signed decimal output,
octal output, unsigned decimal output,
hexadecimal output, floating point
output, and string output, respec-
tively. Some output formats do not
apply to all fields. Floating point
output only applies to timespec fields
(the a, m, and c fields).
The special output specifier S may be
used to indicate that the output, if
applicable, should be in string for-
mat. May be used in combination with:
amc Display date in strftime(3)
format.
dr Display actual device name.
gu Display group or user name.
p Display the mode of file as in
ls -lTd.
N Displays the name of file.
T Displays the type of file.
Y Insert a `` -> '' into the
output. Note that the default
output format for Y is a
string, but if specified
explicitly, these four charac-
ters are prepended.
sub An optional sub field specifier (high,
middle, low). Only applies to the p,
d, r, and T output formats. It can be
one of the following:
H ``High'' -- specifies the
major number for devices from
r or d, the ``user'' bits for
permissions from the string
form of p, the file ``type''
bits from the numeric forms of
p, and the long output form of
T.
L ``Low'' -- specifies the minor
number for devices from r or
d, the ``other'' bits for per-
missions from the string form
of p, the ``user'', ``group'',
and ``other'' bits from the
numeric forms of p, and the ls
-F style output character for
file type when used with T
(the use of L for this is
optional).
M ``Middle'' -- specifies the
``group'' bits for permissions
from the string output form of
p, or the ``suid'', ``sgid'',
and ``sticky'' bits for the
numeric forms of p.
datum A required field specifier, being one
of the following:
d Device upon which file
resides.
i file's inode number.
p File type and permissions.
l Number of hard links to file.
u, g User ID and group ID of file's
owner.
r Device number for character
and block device special
files.
a, m, c, B
The time file was last
accessed or modified, of when
the inode was last changed, or
the birth time of the inode.
z The size of file in bytes.
b Number of blocks allocated for
file.
k Optimal file system I/O opera-
tion block size.
f User defined flags for file.
v Inode generation number.
The following four field specifiers
are not drawn directly from the data
in struct stat, but are:
N The name of the file.
T The file type, either as in ls
-F or in a more descriptive
form if the sub field speci-
fier H is given.
Y The target of a symbolic link.
Z Expands to ``major,minor''
from the rdev field for char-
acter or block special devices
and gives size output for all
others.
Only the % and the field specifier are
required. Most field specifiers default to U
as an output form, with the exception of p
which defaults to O, a, m, and c which default
to D, and Y, T, and N which default to S.
五·退出状态 EXIT STATUS
The stat and readlink utilities exit 0 on suc-
cess, and >0 if an error occurs.
六·示例 EXAMPLES
Given a symbolic link foo that points from
/tmp/foo to /, you would use stat as follows:
> stat -F /tmp/foo
lrwxrwxrwx 1 jschauma cs 1 Apr 24 16:37:28 2002 /tmp/foo@ -> /
> stat -LF /tmp/foo
drwxr-xr-x 16 root wheel 512 Apr 19 10:57:54 2002 /tmp/foo/
To initialize some shell variables, you could
use the -s flag as follows:
> csh
% eval set `stat -s .cshrc`
% echo $st_size $st_mtimespec
1148 1015432481
> sh
$ eval $(stat -s .profile)
$ echo $st_size $st_mtimespec
1148 1015432481
In order to get a list of the kind of files
including files pointed to if the file is a
symbolic link, you could use the following
format:
$ stat -f "%N: %HT%SY" /tmp/*
/tmp/bar: Symbolic Link -> /tmp/foo
/tmp/output25568: Regular File
/tmp/blah: Directory
/tmp/foo: Symbolic Link -> /
In order to get a list of the devices, their
types and the major and minor device numbers,
formatted with tabs and linebreaks, you could
use the following format:
stat -f "Name: %N%n%tType: %HT%n%tMajor: %Hr%n%tMinor: %Lr%n%n" /dev/*
[...]
Name: /dev/wt8
Type: Block Device
Major: 3
Minor: 8
Name: /dev/zero
Type: Character Device
Major: 2
Minor: 12
In order to determine the permissions set on a
file separately, you could use the following
format:
> stat -f "%Sp -> owner=%SHp group=%SMp other=%SLp" .
drwxr-xr-x -> owner=rwx group=r-x other=r-x
In order to determine the three files that
have been modified most recently, you could
use the following format:
> stat -f "%m%t%Sm %N" /tmp/* | sort -rn | head -3 | cut -f2-
Apr 25 11:47:00 2002 /tmp/blah
Apr 25 10:36:34 2002 /tmp/bar
Apr 24 16:47:35 2002 /tmp/foo本文章为转载内容，我们尊重原作者对文章享有的著作权。如有内容错误或侵权问题，欢迎原作者联系我们进行内容更正或删除文章。
