Common formats for executing Linux commands:
Command name [command parameter] [command object]
Command name: It is the "verb" in our grammar, which expresses what we want to do, such as creating users, viewing files, restarting the system, etc.;
command parameters: used to adjust the command to "modify" The command can better fit the work needs and achieve a multiplier effect. Just like buying clothes, the default size will always feel too big or too small, either just wear it, or cut and modify it again. This behavior of "modifying" the
command is called adding parameters; Object: generally refers to the name of the file, directory, user and other resources to be processed, that is, the "receiver" after the command is executed;
