[Common Directory Description] Directory/bin stores binary executable files (ls, cat, mkdir, etc.), and common commands are generally here. /etc stores system management and configuration files/home stores all user files. The root directory of the user's home directory is the basis of the user's home directory. For example, the home directory of the user user is /home/user. You can use ~user to represent /usr to store system applications. The more important directory /usr/local Local system administrator software installation directory (install system-level applications). This is the largest directory, and almost all the applications and files to be used are in this directory. /usr/x11r6?Directory for storing x?window/usr/bin?Many

PHP code can be executed in many ways: 1. Use the command line to directly enter the "php file name" to execute the script; 2. Put the file into the document root directory and access it through the browser through the web server; 3. Run it in the IDE and use the built-in debugging tool; 4. Use the online PHP sandbox or code execution platform for testing.

Reasons for system performance not recovered after uninstalling the Apache service may include resource occupancy by other services, error messages in log files, resource consumption by abnormal processes, network connection problems, and file system residues. First, check whether there are other services or processes before uninstalling with Apache; second, pay attention to the operating system's log files and find error messages that may occur during the uninstallation process; second, check the system's memory usage and CPU load, and find out abnormal processes; then, use the netstat or ss command to view the network connection status to ensure that no ports are occupied by other services; finally, clean up the remaining configuration files and log files after uninstallation to avoid occupying disk space.

Updating the Tomcat version in the Debian system generally includes the following process: Before performing the update operation, be sure to do a complete backup of the existing Tomcat environment. This covers the /opt/tomcat folder and its related configuration documents, such as server.xml, context.xml, and web.xml. The backup task can be completed through the following command: sudocp-r/opt/tomcat/opt/tomcat_backup Get the new version Tomcat Go to ApacheTomcat's official website to download the latest version. According to your Debian system

Understanding Nginx's configuration file path and initial settings is very important because it is the first step in optimizing and managing a web server. 1) The configuration file path is usually /etc/nginx/nginx.conf. The syntax can be found and tested using the nginx-t command. 2) The initial settings include global settings (such as user, worker_processes) and HTTP settings (such as include, log_format). These settings allow customization and extension according to requirements. Incorrect configuration may lead to performance issues and security vulnerabilities.

Configuring Apache to connect to MySQL database requires the following steps: 1. Make sure that Apache and MySQL are installed; 2. Configuring Apache to support PHP, by adding LoadModule and AddHandler instructions in httpd.conf or apache2.conf; 3. Configuring PHP to connect to MySQL, enable mysqli extension in php.ini; 4. Create and test the connected PHP file. Through these steps, the connection between Apache and MySQL can be successfully implemented.

Java middleware is a software that connects operating systems and application software, providing general services to help developers focus on business logic. Typical applications include: 1. Web server (such as Tomcat and Jetty), which handles HTTP requests; 2. Message queue (such as Kafka and RabbitMQ), which handles asynchronous communication; 3. Transaction management (such as SpringTransaction), which ensures data consistency; 4. ORM framework (such as Hibernate and MyBatis), which simplifies database operations.

There are many methods and tools for monitoring Hadoop clusters on Debian systems. The following are some commonly used monitoring tools and their usage methods: Hadoop's own monitoring tool HadoopAdminUI: Access the HadoopAdminUI interface through a browser to intuitively understand the cluster status and resource utilization. HadoopResourceManager: Access the ResourceManager WebUI (usually http://ResourceManager-IP:8088) to monitor cluster resource usage and job status. Hadoop