How to save the unnamed vim in Linux

In Linux, how to save the unnamed vim file on the command terminal, input the vim command, and the vim file will be opened. after the file is edited, The E32: Nofilename will be reminded when it is saved. How to save the unnamed vim? The following describes how to: in command mode, enter file, followed by path and file name to save the file... in Linux, how to save the unnamed vim in the command terminal, input the vim command, and the vim file will be opened. after the file is edited, The E32 will be reminded when it is saved:

No file name. How to save the unnamed vim? In command mode, enter the file, followed by the path and file name to save the file. If this file is named welcome.txt, it is saved in the current directory. Command: view the current directory in file welcome.txt. You can use the cat command to browse the file content. Note: my Linux version is Federa15