4.chdir
chdir ("/home/linux"); "../../"
fopen("1.mp4")
int chdir(const char *path);// /home/linux
功能:
改变当前程序的工作路径
参数:
path:改变到的路径
返回值:
成功返回0
失败返回-1
/home/linux/Desktop/Music
"file.txt"
chdir("/root");
"file.txt"
5.getcwd //pwd
char *getcwd(char *buf, size_t size);
功能:
获得当前的工作路径
参数:
buf:保存工作路径空间的首地址
size:保存路径空间的长度
返回值:
成功返回包含路径空间的字符串首地址
失败返回NULL
6.mkdir
int a =200;
int mkdir(const char *pathname, mode_t mode);//777 666 --x--x--x
功能:
创建一个目录
666-
参数:
pathname:路径
mode:
mode & ~umask 0002
返回值:
成功返回0
失败返回-1
7.rmdir rm -fr rmdir
int rmdir(const char *pathname);
功能:
删除一个空目录文件
参数:
pathname:目录文件的名字
返回值:
成功返回0
失败返回-1
实现ls -l
drwxrwxr-x 2 linux linux 4096 Mar 22 19:31 ./
说明:
d rwx rwx r-x 2 linux linux 4096 Mar 22 19:31 ./
文件类型 相关权限 目录 所有者 所在组 文件大小 最后被修改的时间 文件名
用户 (子目录个数)
所在组 文件
其他人 (硬链接数)
(用户组)
---------------------------
硬链接:
同一个文件，多个名字。
软链接:
某一个文件的快捷方式。
1.stat
int stat(const char *path, struct stat *buf);
功能:
获得文件的属性
参数:
path: 文件的路径
buf: 属性存放空间的首地址
返回值:
成功返回0
失败返回-1
All of these system calls return a stat structure, which contains the following fields:
struct stat {
dev_t st_dev; /* ID of device containing file */ unsigned long int
ino_t st_ino; /* inode number */(*) unsigned long int
mode_t st_mode; /* protection */(* 权限信息) unsigned int
nlink_t st_nlink; /* number of hard links */(* 硬链接数)unsigned int
uid_t st_uid; /* user ID of owner */ (*UID 用户id)unsigned int
gid_t st_gid; /* group ID of owner */(*group 所在组ID)unsigned int
dev_t st_rdev; /* device ID (if special file) */unsigned long long int
off_t st_size; /* total size, in bytes */(*文件的大小)// long unsigned int
blksize_t st_blksize; /* blocksize for file system I/O */ long int
blkcnt_t st_blocks; /* number of 512B blocks allocated */long int
time_t st_atime; /* time of last access */(*最后访问的时间)long unsigned int
time_t st_mtime; /* time of last modification */ (*最后修改的时间)
time_t st_ctime; /* time of last status change */(*最后的状态改变的时间)
};
st_mode --- 32位
1111 0000 0000 0000
S_IFMT 0170000 bit mask for the file type bit fields
S_IFSOCK 0140000 socket //s 1100
S_IFLNK 0120000 symbolic link //l 1010
S_IFREG 0100000 regular file //- 1000
S_IFBLK 0060000 block device //b 110
S_IFDIR 0040000 directory //d 100
S_IFCHR 0020000 character device //c 010
S_IFIFO 0010000 FIFO //p 001
S_ISUID 0004000 set UID bit
S_ISGID 0002000 set-group-ID bit (see below)
S_ISVTX 0001000 sticky bit (see below)
//user
S_IRWXU 00700 mask for file owner permissions
S_IRUSR 00400 owner has read permission
S_IWUSR 00200 owner has write permission
S_IXUSR 00100 owner has execute permission
//group
S_IRWXG 00070 mask for group permissions
S_IRGRP 00040 group has read permission
S_IWGRP 00020 group has write permission
S_IXGRP 00010 group has execute permission
//others //掩码
S_IRWXO 00007 mask for permissions for others (not in group)
S_IROTH 00004 others have read permission
S_IWOTH 00002 others have write permission
S_IXOTH 00001 others have execute permission
