以下是用linux C写的实现wc功能的函数
#include
#define BEGIN 1;
int main(int argc, char *argv[])
{
int characters, lines, words, state;
char c;
state = characters = lines = words = 0;
while((c = getchar()) != '0') {
characters++;
if(c == '\n') {
lines++;
state = 0;
continue;
} else if(c == ' ') {
state = 0;
continue;
} else if(c == '\t') {
state = 0;
continue;
} else {
if(state == 0) {
state = BEGIN;
words++;
}
continue;
}
}
printf("%d characters. %d words. %d lines.\n", characters, words, lines);
}
以下是用linux C写的实现ls部分功能的函数。
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
//用lstat函数获取文件的类型
int get_mode(char *file)
{
struct stat buf;
char *ptr;
if(lstat(file, &buf) < 0)
{
printf("error\n!");
}
switch(S_IFMT&buf.st_mode)
{
case S_IFREG:ptr = "-";break;
case S_IFDIR:ptr = "d";break;
case S_IFCHR:ptr = "c";break;
case S_IFBLK:ptr = "b";break;
case S_IFIFO:ptr = "f";break;
case S_IFLNK:ptr = "l";break;
case S_IFSOCK:ptr = "s";break;
default:ptr = "UNKNOW";
}
printf("%s", ptr);
return 0;
}
//用stat获取文件拥有者，用户组和其他组的权限
int get_rwx(char *file)
{
struct stat buf;
if(stat(file, &buf) == -1)
{
perror("stat \n");
return 0;
}
//文件拥有者的权限获取
if(S_IRUSR&buf.st_mode) {
printf("r");
} else {
printf("-");
}
if(S_IWUSR&buf.st_mode) {
printf("w");
} else {
printf("-");
}
if(S_IXUSR&buf.st_mode) {
printf("x");
} else {
printf("-");
}
//文件用户组的权限获取
if(S_IRGRP&buf.st_mode) {
printf("r");
} else {
printf("-");
}
if(S_IWGRP&buf.st_mode) {
printf("w");
} else {
printf("-");
}
if(S_IXGRP&buf.st_mode) {
printf("x");
} else {
printf("-");
}
//文件其他组的权限获取
if(S_IROTH&buf.st_mode) {
printf("r");
} else {
printf("-");
}
if(S_IWOTH&buf.st_mode) {
printf("w");
} else {
printf("-");
}
if(S_IXOTH&buf.st_mode) {
printf("x");
} else {
printf("-");
}
return 0;
}
//获取文件的大小
long get_size(char *file)
{
struct stat buf;
long n;
stat(file, &buf);
n = buf.st_size;
return n;
}
//获取文件的修改时间
int get_time(char *file, char *ch)
{
struct stat buf;
stat(file, &buf);
strcpy(ch, ctime(&buf.st_mtime));
ch[strlen(ch) - 1] = '\0';
return 0;
}
//文件的硬链接数目,并且打印出来
int get_nlink(char *file)
{
struct stat buf;
stat(file, &buf);
printf(" %d", buf.st_nlink);
return 0;
}
//获取文件拥有者和用户组的name
int get_name(char *file)
{
struct stat buf;
char name1[20], name2[20];
stat(file, &buf);
strcpy(name1, getpwuid(buf.st_uid)->pw_name);
strcpy(name2, getpwuid(buf.st_gid)->pw_name);
printf(" %s %s", name1, name2);
return 0;
}
//浏览文件夹的内容
struct dirent **scan_dir(int *n)
{
struct dirent **namelist;
(*n) = scandir(".", &namelist, 0, alphasort);
if ((*n) < 0)
perror("scandir");
return namelist;
}
//实现ls不带参数的命令
int no_ls()
{
struct dirent **namelist;
int i, n;
long all_size = 0, size;
namelist = scan_dir(&n);
for(i = 0; i < n; i++) {
if(namelist[i]->d_name[0] != '.') {
printf("%-s ", namelist[i]->d_name);
}
free(namelist[i]);
}
printf("\n");
free(namelist);
return 0;
}
//实现ls -l的命令
int l_ls()
{
struct dirent **namelist;
int n, i;
long all_size = 0, size;
char ch[40] = {0};
namelist = scan_dir(&n);
//得到文件总的大小
for(i = 0; i < n; i++) {
if(namelist[i]->d_name[0] != '.') {
size = get_size(namelist[i]->d_name);
all_size += size;
}
}
//打印信息
printf("总用量:%ld\n", all_size);
for(i = 0; i < n; i++) {
if(namelist[i]->d_name[0] != '.') {
get_mode(namelist[i]->d_name);
get_rwx(namelist[i]->d_name);
get_nlink(namelist[i]->d_name);
get_name(namelist[i]->d_name);
printf(" %5ld", get_size(namelist[i]->d_name));
get_time(namelist[i]->d_name, ch);
printf(" %s", ch);
printf(" %s", namelist[i]->d_name);
printf("\n");
}
free(namelist[i]);
}
free(namelist);
return 0;
}
//实现ls -al的命令
int al_ls()
{
struct dirent **namelist;
int n, i;
long all_size = 0, size;
char ch[40] = {0};
namelist = scan_dir(&n);
//得到文件总的大小
for(i = 0; i < n; i++) {
size = get_size(namelist[i]->d_name);
all_size += size;
}
printf("总用量:%ld\n", all_size);
for(i = 0; i < n; i++) {
get_mode(namelist[i]->d_name);
get_rwx(namelist[i]->d_name);
get_nlink(namelist[i]->d_name);
get_name(namelist[i]->d_name);
all_size += size;
printf(" %5ld", get_size(namelist[i]->d_name));
get_time(namelist[i]->d_name, ch);
printf(" %s", ch);
printf(" %s", namelist[i]->d_name);
printf("\n");
free(namelist[i]);
}
free(namelist);
return 0;
}
//实现ls -a的命令
int a_ls()
{
struct dirent **namelist;
int i, n;
namelist = scan_dir(&n);
for(i = 0; i < n; i++) {
printf("%-s ", namelist[i]->d_name);
free(namelist[i]);
}
printf("\n");
free(namelist);
return 0;
}
//实现ls -A的命令
int A_ls()
{
struct dirent **namelist;
int i, n, test1, test2;
namelist = scan_dir(&n);
for(i = 0; i < n; i++) {
test1 = strcmp(".", namelist[i]->d_name) == 0;
test2 = strcmp("..", namelist[i]->d_name) == 0;
if(test1 || test2){
free(namelist[i]);
continue;
}
printf("%-s ", namelist[i]->d_name);
free(namelist[i]);
}
printf("\n");
free(namelist);
return 0;
}
//浏览指定目录下的文件
int dir_ls(char *name)
{
struct dirent **namelist;
char file[20] = {0};
int i, n;
strcpy(file, "./");
strcat(file, name);
printf("%s\n", name);
n = scandir(file, &namelist, 0, alphasort);
for(i = 0; i < n; i++) {
if(namelist[i]->d_name[0] == '.') {
free(namelist[i]);
continue;
}
printf("%-s ", namelist[i]->d_name);
free(namelist[i]);
}
printf("\n");
free(namelist);
return 0;
}
//实现多个输入文件时的输出name_ls
int name_ls(int argc, char **argv)
{
int i;
struct stat buf;
for(i = 1; i < argc; i++) {
if(lstat(argv[i], &buf) < 0) {
perror("lstat:\n");
}
switch(S_IFMT&buf.st_mode) {
case S_IFDIR:dir_ls(argv[i]);break;
default:file_ls(argv[i]);
}
}
return 0;
}
//实现file_ls
int file_ls(char *file)
{
int fd;
struct stat buf;
if(lstat(file, &buf) < 0) {
perror("lstat:\n");
return 0;
}
switch(S_IFMT&buf.st_mode) {
case S_IFDIR:dir_ls(file);return 0;
}
if((fd = open(file, O_RDONLY)) == -1) {
printf("没有找到%s文件!\n", file);
} else {
close(fd);
printf("%s\n", file);
}
return 0;
}
//实现mylist
int mylist(char *option)
{
if(strcmp(option, "-l") == 0) {
l_ls();
} else if(strcmp(option, "-al") == 0 || strcmp(option, "-la") == 0) {
al_ls();
} else if(strcmp(option, "-a") == 0) {
a_ls();
} else if(strcmp(option, "-A") == 0) {
A_ls();
} else {
file_ls(option);
}
return 0;
}
//主函数
int main(int argc, char *argv[])
{
if(argc == 1) {
no_ls();
} else if(argc == 2) {
mylist(argv[1]);
} else if(argc > 2) {
name_ls(argc, argv);
} else {
perror("Input error!\n");
}
return 0;
}
