stat命令的学习与C语言实现
stat命令的学习
man stat
STAT(1) User Commands STAT(1)
NAME
stat - display file or file system status
SYNOPSIS
stat [OPTION]... FILE...
DESCRIPTION
Display file or file system status.
Mandatory arguments to long options are mandatory for short options
too.
-L, --dereference
follow links
-f, --file-system
display file system status instead of file status
-c --format=FORMAT
use the specified FORMAT instead of the default; output a new‐
line after each use of FORMAT
--printf=FORMAT
like --format, but interpret backslash escapes, and do not out‐
put a mandatory trailing newline; if you want a newline, include
\n in FORMAT
-t, --terse
print the information in terse form
--help display this help and exit
--version
output version information and exit
The valid format sequences for files (without --file-system):
%a access rights in octal (note '#' and '0' printf flags)
%A access rights in human readable form
%b number of blocks allocated (see %B)
%B the size in bytes of each block reported by %b
%C SELinux security context string
%d device number in decimal
%D device number in hex
%f raw mode in hex
%F file type
%g group ID of owner
%G group name of owner
%h number of hard links
%i inode number
%m mount point
%n file name
%N quoted file name with dereference if symbolic link
%o optimal I/O transfer size hint
%s total size, in bytes
%t major device type in hex, for character/block device special
files
%T minor device type in hex, for character/block device special
files
%u user ID of owner
%U user name of owner
%w time of file birth, human-readable; - if unknown
%W time of file birth, seconds since Epoch; 0 if unknown
%x time of last access, human-readable
%X time of last access, seconds since Epoch
%y time of last data modification, human-readable
%Y time of last data modification, seconds since Epoch
%z time of last status change, human-readable
%Z time of last status change, seconds since Epoch
Valid format sequences for file systems:
%a free blocks available to non-superuser
%b total data blocks in file system
%c total file nodes in file system
%d free file nodes in file system
%f free blocks in file system
%i file system ID in hex
%l maximum length of filenames
%n file name
%s block size (for faster transfers)
%S fundamental block size (for block counts)
%t file system type in hex
%T file system type in human readable form
--terse is equivalent to the following FORMAT:
%n %s %b %f %u %g %D %i %h %t %T %X %Y %Z %W %o %C
--terse --file-system is equivalent to the following FORMAT:
%n %i %l %t %s %S %b %f %a %c %d
NOTE: your shell may have its own version of stat, which usually super‐
sedes the version described here. Please refer to your shell's docu‐
mentation for details about the options it supports.
AUTHOR
Written by Michael Meskes.
REPORTING BUGS
GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
Report stat translation bugs to <https://translationproject.org/team/>
COPYRIGHT
Copyright © 2018 Free Software Foundation, Inc. License GPLv3+: GNU
GPL version 3 or later <https://gnu.org/licenses/gpl.html>.
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.
stat命令参数
-L, --dereference 跟随链接
-f, --file-system 显示文件系统状态而非文件状态
-c --format=FORMAT use the specified FORMAT instead of the default;
output a newline after each use of FORMAT
--printf=FORMAT like --format, but interpret backslash escapes,
and do not output a mandatory trailing newline;
if you want a newline, include \n in FORMAT
-t, --terse print the information in terse form
--help 显示此帮助信息并退出
--version 显示版本信息并退出
stat函数结构体
struct stat {
dev_t st_dev; /* ID of device containing file */
ino_t st_ino; /* Inode number */
mode_t st_mode; /* File type and mode */
nlink_t st_nlink; /* Number of hard links */
uid_t st_uid; /* User ID of owner */
gid_t st_gid; /* Group ID of owner */
dev_t st_rdev; /* Device ID (if special file) */
off_t st_size; /* Total size, in bytes */
blksize_t st_blksize; /* Block size for filesystem I/O */
blkcnt_t st_blocks; /* Number of 512B blocks allocated */
}
产品代码：
#include <sys/types.h>
#include <sys/stat.h>
#include <time.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/sysmacros.h>
#include <unistd.h>
#include <sys/types.h>
#include <pwd.h>
#include <string.h>
#include <time.h>
#include <sys/timeb.h>
struct stat sb;
struct tm *lt;
struct tm stm;
time_t t;
void timeswitch(struct tm *lt)
{
char nowtime[24];
memset(nowtime, 0, sizeof(nowtime));
strftime(nowtime, 24, "%Y-%m-%d %H:%M:%S", lt);
printf("%s\n", nowtime);
}
int main(int argc, char *argv[])
{
int n;
struct passwd *pwd;
// = getpwuid(sb.st_uid);
char nowtime[24];
int count[3]={0};
int cou = 0;
int flag = 0;
char mode[8]={0};
if (argc != 2)
{
fprintf(stderr, "Usage: %s <pathname>\n", argv[0]);
exit(EXIT_FAILURE);
}
if (lstat(argv[1], &sb) == -1)
{
perror("lstat");
exit(EXIT_FAILURE);
}
printf(" 文件： %s\n",argv[1]);
printf(" 大小: %lld bytes ",(long long) sb.st_size);
printf("块: %lld ",(long long) sb.st_blocks);
printf("I/O 块: %ld ",(long) sb.st_blksize);
switch (sb.st_mode & S_IFMT)
{
case S_IFBLK: printf("块设备\n"); break;
case S_IFCHR: printf("字符设备\n"); break;
case S_IFDIR: printf("目录\n"); flag=1; break;
case S_IFIFO: printf("FIFO/管道\n"); break;
case S_IFLNK: printf("symlink\n"); break;
case S_IFREG: printf("普通文件\n"); break;
case S_IFSOCK: printf("socket\n"); break;
default: printf("unknown?\n"); break;
}
printf("设备：%ld ",(long)sb.st_dev);
printf("Inode: %ld ", (long) sb.st_ino);
printf("硬链接: %ld\n", (long) sb.st_nlink);
printf("权限：");
printf("（");
for(n=8;n>=0;n--)
{
if(sb.st_mode&(1<<n))
{
switch(n%3)
{
case 2:
mode[8-n] = 'r';
count[n/3] += 4;
break;
case 1:
mode[8-n] = 'w';
count[n/3] += 2;
break;
case 0:
mode[8-n] = 'x';
count[n/3] += 1;
break;
default:
break;
}
}
else
{
mode[8-n] = '-';
}
}
printf("0%d%d%d/",count[2],count[1],count[0]);
if(flag)
{
printf("d");
}
else
{
printf("-");
}
for ( cou = 0; cou <= 8; cou++)
{
printf("%c",mode[cou]);
}
printf("） ");
pwd = getpwuid(sb.st_uid);
printf("UID: ( %ld/ %s) GID: ( %ld/ %s )\n",(long) sb.st_uid,pwd->pw_name, (long) sb.st_gid,pwd->pw_name);
printf("最近访问: ");
timeswitch(localtime(&sb.st_atime));
printf("最近更改: ");
timeswitch(localtime(&sb.st_ctime));
printf("最近改动: ");
timeswitch(localtime(&sb.st_mtime));
printf("创建时间: -\n");
exit(EXIT_SUCCESS);
}
对比截图：
