There are two main ways to install PHP on Linux: use package manager to install and source code to compile and install. For newbies or users who do not have special requirements for the version, it is recommended to use a package manager to install it. For example, running sudoaptupdate and sudoaptinstallphp on Ubuntu/Debian. On CentOS, you can first install the EPEL source and then install it with yum. After the installation is completed, you can verify through php-v and install common extensions. If you need a specific version or custom function, you should choose source code compilation and installation. The specific steps include downloading the source code package, decompression, and configuration (such as ./configure--prefix=/usr/local/php--with-co

Yes,PHPsupportsmultilinecommentsusingthe/.../syntax.Towritethem,enclosetextbetween/and/,whichcanspanmultiplelinesandisignoredbytheinterpreter.Theyareidealforlongexplanations,disablingcodeblocksduringtesting,oraddingfileheaders.Avoidnestingthem,asitbr

When writing PHP comments, you should clarify the purpose, logic and structure. 1. Each function and class uses DocBlock format to explain the role, parameters and return values; 2. Explain "why" in the key logic rather than just "what was done"; 3. Add a brief description at the top of the file, including functions, dependencies and usage scenarios; 4. Avoid nonsense comments, add only necessary instructions before complex logic, and do not record the modification history. This improves code readability and maintenance efficiency.

Of course it is useful. PHP still plays an important role in web development, especially for CMS and e-commerce platforms. 1. The threshold for PHP is low, the syntax is intuitive, and suitable for beginners to get started; 2. It is widely used in dynamic web development, such as user login, form submission and other functions; 3. It can build an API interface, which is more efficient with the Laravel framework; 4. It supports CMS customization, such as WordPress plug-in and theme development; 5. It can write automated task scripts, such as data crawling and report generation; 6. Learning suggestions include mastering basic syntax, combining database exercise projects, using mainstream frameworks, focusing on security defense and referring to open source projects. PHP is highly practical and has a mature ecological environment, and is still widely used in small and medium-sized projects.

PHPblockcommentsareusefulforwritingmulti-lineexplanations,temporarilydisablingcode,andgeneratingdocumentation.Theyshouldnotbenestedorleftunclosed.BlockcommentshelpindocumentingfunctionswithPHPDoc,whichtoolslikePhpStormuseforauto-completionanderrorche

PHP has 8 main data types, which are divided into scalar types (boolean, integer, float, string), compound types (array, object) and special types (resource, null); where null means that the variable has no value. PHP is a weak-type language, and variables will automatically convert types. For example, adding 10 to a string "123" will turn into an integer 133, but strings that do not start with numbers will turn into 0, which can easily cause errors. It is recommended to manually determine or convert the type when processing input or interface data. Check the type of functions such as is_bool(), is_int(), etc.; casting can be used for (type) or settype() functions.

Install the PHP interpreter and use package management tools such as Ubuntu's apt or macOS Homebrew installation; 2. Use web servers such as Apache or Nginx, Apache automatically loads PHP modules, and Nginx needs to be matched with PHP-FPM; 3. Install database support such as MySQL and other extensions and enables it; 4. Use modern editors such as VSCode, PhpStorm and debugging tools Xdebug to improve development efficiency.

Annotations should be avoided in PHP development: 1. Do not comment sensitive information, such as database passwords or API keys, because these will still be exposed. It is recommended to use environment variables and add .gitignore; 2. Avoid outdated or incorrect comments. When modifying the code, you need to update the comments simultaneously to ensure the description is accurate; 3. Do not write meaningless comments. If you add redundant instructions to simple assignment statements, comments should be added in complex logic; 4. Do not replace PHPDoc document comments with ordinary comments. It is recommended to use standard formats to support IDE prompts and maintain structured information.