nginx启动，重启，关闭命令 (另：kill -USR2 的作用)

<?php

class student
{
public $name; //姓名
public $id;
public $gender; // 性别
public $chinese;
public $math;
public $english;
public $computer;
public $prev = null; //前节点
public $next = null; //后节点

function __construct($name="",$id="",$gender="",$chinese="",$math="",$english="",$computer="") {
$this->name = $name;
$this->id = $id;
$this->gender = $gender;
$this->chinese = $chinese;
$this->math = $math;
$this->english = $english;
$this->computer = $computer;
}

public static function findStudent($head,$student,$type='id')
{
$temp = $head;
$isFind = false;
while (!is_null($temp)) {
if ($temp->$type == $student->$type) {
$isFind = true;
break;
}
$temp=$temp->next;
}
if ($isFind) {
echo "\n找到：学生姓名：".$temp->name." 学号:".$temp->id." 性别：".$temp->gender." 语文：".$temp->chinese." 数学：".$temp->math." 英语：".$temp->english." 计算机:".$temp->computer."";
}else {
echo "没有找到该学生信息";
}
}

/**
* 添加学生信息
*
* @param unknown_type $head
* @param unknown_type $student
*/
public static function insertStudent($head,$student)
{
$temp = $head;
if(is_null($temp->next)){
$temp->next = $student;
$student->prev = $temp;
}else{
$isAdd = true;
while ( !is_null($temp->next)) {
if ($temp->next->id > $student->id) {
break;
}elseif ($temp->next->id == $student->id)
{
echo "学号相同";
$isAdd = false;
}
$temp = $temp->next;
}
if ($isAdd) {
$student->next = $temp->next;
$student->prev = $temp;
//$temp->next->prev = $student;
$temp->next = $student;
}
}
}

/**
* 删除学生信息
*
* @param unknown_type $head
* @param unknown_type $student
*/
public static function delStudent($head,$student)
{
$temp = $head->next;
$isFind = false;
while (!is_null($temp)) {
if ($temp->id == $student->id) {
$isFind = true;
break;
}
$temp=$temp->next;
}
if ($isFind) {
if (!is_null($temp->next)) {
$temp->next->prev=$temp->prev;
}
$temp->prev->next=$temp->next;

echo "删除的学生为".$temp->name." 学号:".$temp->id." 性别：".$temp->gender." 语文：".$temp->chinese." 数学：".$temp->math." 英语：".$temp->english." 计算机:".$temp->computer."";
}else {
echo "没有找到该学生信息";
}
}

/**
* 展示全部学生信息
*
* @param unknown_type $head
*/
public static function showAllStudent($head)
{
$temp = $head->next;
while (!is_null($temp)) {
echo "\n学生姓名：".$temp->name." 学号:".$temp->id." 性别：".$temp->gender." 语文：".$temp->chinese." 数学：".$temp->math." 英语：".$temp->english." 计算机:".$temp->computer."";
$temp=$temp->next;
}
}
}

$head = new student();
$student1 = new student("张永伟","98","男","100","100","100","100");
$student2 = new student("魏海龙","99","男","100","100","100","100");
$student3 = new student("宋老师","100","男","100","100","100","100");
$student4 = new student("杨老师","97","男","100","100","100","100");
$student5 = new student("李杰","96","男","100","100","100","100");

student::insertStudent($head,$student1);
student::insertStudent($head,$student2);
student::insertStudent($head,$student3);
student::insertStudent($head,$student4);
student::insertStudent($head,$student5);
echo "\n删除宋老师:\n";
student::delStudent($head,$student3);
echo "\n全部学生信息遍历：";
student::showAllStudent($head);

echo "\n查找学生张永伟：";
student::findStudent($head,$student1);
?>