类似ls命令程序

# include <stdio.h># include <sys/types.h># include <dirent.h># include <sys/stat.h># include <unistd.h># include <time.h># include <string.h># include <pwd.h># include <grp.h>void do_ls(char []);void do_stat(char *);void show_file_info(char *, struct stat *);void mode_to_letters(int mode, char * modestr);char * uid_to_name(uid_t);char * gid_to_name(gid_t);int main(int argc, char *argv[]){if(argc == 1)do_ls(".");elsewhile(--argc){printf("%s:\n", *(++argv));do_ls(*argv);}}/*do ls the list files in directory*/void do_ls(char dirname[]){DIR *dir_ptr;struct dirent *dir_struct;if((dir_ptr = opendir(dirname)) == NULL)perror(dirname);else{while((dir_struct = readdir(dir_ptr)) != NULL)do_stat(dir_struct->d_name);closedir(dir_ptr);}}/*get the file information*/void do_stat(char *filename){struct stat info;if(stat(filename, &info) == -1)perror(filename);elseshow_file_info(filename, &info);}/*show the file information*/void show_file_info(char *filename, struct stat *info_ptr){char modestr[11];mode_to_letters(info_ptr->st_mode, modestr);printf("%s", modestr);printf("%4d", info_ptr->st_nlink);printf("%-8s", uid_to_name(info_ptr->st_uid));printf("%-8s", gid_to_name(info_ptr->st_gid));printf("%8ld", info_ptr->st_size);printf("%.12s", 4 + ctime(&info_ptr->st_mtime));printf("%s\n", filename);}/*ID to string*/void mode_to_letters(int mode, char *modestr){strcpy(modestr, "----------");if(S_ISDIR(mode))modestr[0] = 'd';if(S_ISCHR(mode))modestr[0] = 'c';if(S_ISBLK(mode))modestr[0] = 'b';if(mode & S_IRUSR)modestr[1] = 'r';if(mode & S_IWUSR)modestr[2] = 'w';if(mode & S_IXUSR)modestr[3] = 'x';if(mode & S_IRGRP)modestr[4] = 'r';if(mode & S_IWGRP)modestr[5] = 'w';if(mode & S_IXGRP)modestr[6] = 'x';if(mode & S_IROTH)modestr[7] = 'r';if(mode & S_IWOTH)modestr[8] = 'w';if(mode & S_IXOTH)modestr[9] = 'x';}/*get the username for string*/char * uid_to_name(uid_t uid){struct passwd * pw_ptr;static char numstr[10];if((pw_ptr = getpwuid(uid)) == NULL){sprintf(numstr, "%d", uid);return numstr;}elsereturn pw_ptr->pw_name;}/*get the groupname for string*/char * gid_to_name(gid_t gid){struct group * gr_ptr;static char numstr[10];if((gr_ptr = getgrgid(gid)) == NULL){sprintf(numstr, "%d", gid);return numstr;}elsereturn gr_ptr->gr_name;}