一、在终端打印文件属性

1. 从终端获取一个文件的路径以及名字
2. 若该文件是目录文件，则将该文件下的所有文件的属性打印到终端
3. 若该文件不是目录文件，则打印该文件的属性到终端

#include <stdio.h>
#include <string.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <time.h>
#include <pwd.h>
#include <grp.h>
#include <dirent.h>
#include <errno.h>void get_fileType(mode_t m)
{if(S_ISREG(m))putchar('-');else if(S_ISDIR(m))putchar('d');else if(S_ISCHR(m))putchar('c');else if( S_ISBLK(m))putchar('b');else if( S_ISFIFO(m))putchar('p');else if( S_ISLNK(m))putchar('l');else if( S_ISSOCK(m))putchar('s');
}void get_filePermission(mode_t m)
{long x = 0400;char c[]="rwx";int count = 0; while(x){if((m & x) == 0)putchar('-');elseprintf("%c",c[count%3]);count++;x = x >> 1;}putchar(' ');
}int getstat(char *str)
{struct stat buf;if(stat(str,&buf) < 0){perror("stat");return -1;}//获取文件类型和权限//	printf("0%o ",buf.st_mode);get_fileType(buf.st_mode);get_filePermission(buf.st_mode);//获取文件的硬链接数printf("%ld ",buf.st_nlink);//获取文件所属用户//	printf("%d ",buf.st_uid);struct passwd *uid = getpwuid(buf.st_uid);printf("%s ",uid->pw_name);//获取文件所属组用户//	printf("%d ",buf.st_gid);struct group *gid = getgrgid(buf.st_gid);printf("%s ",gid->gr_name);//获取文件大小printf("%ld ",buf.st_size);//获取时间戳struct tm *info=NULL;info = localtime(&buf.st_mtime);//	printf("%ld ",buf.st_ctime);printf("%02d %02d %02d:%02d ",info->tm_mon+1,info->tm_mday,info->tm_hour,info->tm_min);printf("%s\n",str);
}int main(int argc, const char *argv[])
{char str[20]="";printf("please enter a filename:");scanf("%s",str);struct stat buf;if(stat(str,&buf) < 0){perror("stat");return -1;}if((buf.st_mode & S_IFMT) == S_IFDIR){DIR * dp = opendir(str);if(NULL == dp){perror("openrid");return -1;}printf("open success \n");struct dirent *rp = NULL;int i=0;while(1){rp = readdir(dp);if(NULL == rp){if(0 == errno){printf("读取完毕\n");break;}else{perror("readdir");return -1;}}if(*(rp->d_name) != '.')getstat(rp->d_name);//	printf("[%d]%s\n",++i,rp->d_name);}closedir(dp);}elsegetstat(str);return 0;
}

 二、文件IO函数实现，拷贝文件，子进程先拷贝后半部分，父进程再拷贝前半部分，允许使用sleep函数

#include <stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
int main(int argc, const char *argv[])
{int fd = open("1.txt",O_RDONLY);char str[128]="";if(fd < 0){perror("open");return -1;}off_t size = lseek(fd,0,SEEK_END);pid_t cpid = fork();if(cpid > 0){sleep(1);lseek(fd,0,SEEK_SET);read(fd,str,size/2);printf("%s",str);}if(cpid == 0){lseek(fd,size/2,SEEK_SET);read(fd,str,size/2);printf("%s",str);}close(fd);while(1){}return 0;
}