C++实现模拟shell命令行(代码解析)

void parse(){
    std::string line;
    getline(std::cin, line);
    
    int len = line.size(), i=0;

    std::string tmp;
    std::vector<std::string> tmp_vc;
    while(i < line.size()){
        if(line[i] == ' '){
            i++;
            continue;
        }
        if(line[i] == '|') {
            vc.push_back(tmp_vc);
            tmp = "";
            i++;
            continue;
        }
        int pos = line.find(' ', i);    // 获取下一个空格的位置
        tmp = line.substr(i, pos-i);    // 截取字符串
        tmp_vc.push_back(tmp);
        i = pos;
    }
    vc.push_back(tmp_vc);
}

void func(std::vector<std::string>& v){
    char *arr[10];
    pid_t pid;
    pid = fork();
    if(pid == -1){
        std::cout << "fork error" << std::endl;
        exit(1);
    }else if(pid ==0){
        for(int i=0; i<v.size(); ++i)
            arr[i] = (char *)v[i].c_str();
        arr[v.size()] = NULL;
        execvp(arr[0], arr);
    }else{
        wait(NULL);
    }
}


void execCommnd(){
    for(int i=0; i<vc.size(); ++i){
        func(vc[i]);
    }
}

void getCurPwd(){
    std::string s = get_current_dir_name();
    int pos  = s.rfind('/');
    std::string tmp = s.substr(pos+1, s.length()-pos);
    std::cout << tmp << "]# ";
}


void getIdname(){
    struct  passwd *pwd;
    pwd = getpwuid(getuid());
    std::cout << "["  <<pwd->pw_name << "@";
}


void getHostName(){
    char buf_w[128];
    int hostname = gethostname(buf_w, sizeof(buf_w)); 
    std::cout << buf_w << " ";
    
}


void showMenu(){
    getIdname();
    getHostName();
    getCurPwd();
}

#include <iOStream>
#include <string>
#include <cstring>
#include <vector>
#include <unistd.h>
#include <stdlib.h>
#include <sys/types.h>
#include <pwd.h>
#include <wait.h>


std::vector<std::vector<std::string>> vc;


void parse(){
    std::string line;
    getline(std::cin, line);
    
    int len = line.size(), i=0;

    std::string tmp;
    std::vector<std::string> tmp_vc;
    while(i < line.size()){
        if(line[i] == ' '){
            i++;
            continue;
        }
        if(line[i] == '|') {
            vc.push_back(tmp_vc);
            tmp = "";
            i++;
            continue;
        }
        int pos = line.find(' ', i);                // 获取下一个空格的位置
        tmp = line.substr(i, pos-i);    // 截取字符串
        tmp_vc.push_back(tmp);
        i = pos;
    }
    vc.push_back(tmp_vc);
}


void func(std::vector<std::string>& v){
    char *arr[10];
    pid_t pid;
    pid = fork();
    if(pid == -1){
        std::cout << "fork error" << std::endl;
        exit(1);
    }else if(pid ==0){
        for(int i=0; i<v.size(); ++i)
            arr[i] = (char *)v[i].c_str();
        arr[v.size()] = NULL;
        execvp(arr[0], arr);
    }else{
        wait(NULL);
    }
}


void execCommnd(){
    for(int i=0; i<vc.size(); ++i){
        func(vc[i]);
    }
}


void getCurPwd(){
    std::string s = get_current_dir_name();
    int pos  = s.rfind('/');
    std::string tmp = s.substr(pos+1, s.length()-pos);
    std::cout << tmp << "]# ";
}


void getIdname(){
    struct  passwd *pwd;
    pwd = getpwuid(getuid());
    std::cout << "["  <<pwd->pw_name << "@";
}


void getHostName(){
    char buf_w[128];
    int hostname = gethostname(buf_w, sizeof(buf_w)); 
    std::cout << buf_w << " ";
    
}


void showMenu(){
    getIdname();
    getHostName();
    getCurPwd();
}

void test(){
    while(1){
        showMenu();
        parse();
        execCommnd();
    }
}

int main(int arGC, char* argv[])
{
    test();
    return 0;
}