What are the 20 most commonly used commands in Linux?

The main reasons why you cannot log in to MySQL as root are permission problems, configuration file errors, password inconsistent, socket file problems, or firewall interception. The solution includes: check whether the bind-address parameter in the configuration file is configured correctly. Check whether the root user permissions have been modified or deleted and reset. Verify that the password is accurate, including case and special characters. Check socket file permission settings and paths. Check that the firewall blocks connections to the MySQL server.

C language conditional compilation is a mechanism for selectively compiling code blocks based on compile-time conditions. The introductory methods include: using #if and #else directives to select code blocks based on conditions. Commonly used conditional expressions include STDC, _WIN32 and linux. Practical case: Print different messages according to the operating system. Use different data types according to the number of digits of the system. Different header files are supported according to the compiler. Conditional compilation enhances the portability and flexibility of the code, making it adaptable to compiler, operating system, and CPU architecture changes.

1.0.1 Preface This project (including code and comments) was recorded during my self-taught Rust. There may be inaccurate or unclear statements, please apologize. If you benefit from it, it's even better. 1.0.2 Why is RustRust reliable and efficient? Rust can replace C and C, with similar performance but higher security, and does not require frequent recompilation to check for errors like C and C. The main advantages include: memory security (preventing null pointers from dereferences, dangling pointers, and data contention). Thread-safe (make sure multi-threaded code is safe before execution). Avoid undefined behavior (e.g., array out of bounds, uninitialized variables, or access to freed memory). Rust provides modern language features such as generics

The five basic components of Linux are: 1. The kernel, managing hardware resources; 2. The system library, providing functions and services; 3. Shell, the interface for users to interact with the system; 4. The file system, storing and organizing data; 5. Applications, using system resources to implement functions.

There are many reasons why MySQL startup fails, and it can be diagnosed by checking the error log. Common causes include port conflicts (check port occupancy and modify configuration), permission issues (check service running user permissions), configuration file errors (check parameter settings), data directory corruption (restore data or rebuild table space), InnoDB table space issues (check ibdata1 files), plug-in loading failure (check error log). When solving problems, you should analyze them based on the error log, find the root cause of the problem, and develop the habit of backing up data regularly to prevent and solve problems.

MySQL cannot run directly on Android, but it can be implemented indirectly by using the following methods: using the lightweight database SQLite, which is built on the Android system, does not require a separate server, and has a small resource usage, which is very suitable for mobile device applications. Remotely connect to the MySQL server and connect to the MySQL database on the remote server through the network for data reading and writing, but there are disadvantages such as strong network dependencies, security issues and server costs.

The C language function library is a toolbox containing various functions, which are organized in different library files. Adding a library requires specifying it through the compiler's command line options, for example, the GCC compiler uses the -l option followed by the abbreviation of the library name. If the library file is not under the default search path, you need to use the -L option to specify the library file path. Library can be divided into static libraries and dynamic libraries. Static libraries are directly linked to the program at compile time, while dynamic libraries are loaded at runtime.

The solution to MySQL installation error is: 1. Carefully check the system environment to ensure that the MySQL dependency library requirements are met. Different operating systems and version requirements are different; 2. Carefully read the error message and take corresponding measures according to prompts (such as missing library files or insufficient permissions), such as installing dependencies or using sudo commands; 3. If necessary, try to install the source code and carefully check the compilation log, but this requires a certain amount of Linux knowledge and experience. The key to ultimately solving the problem is to carefully check the system environment and error information, and refer to the official documents.