What is the function of linux file editing command vi?

The vi command is used to enter vi, the most versatile full-screen plain text editor in the UNIX operating system. The vi editor supports edit mode and command mode. In the edit mode, you can complete the text editing function, and in the command mode, you can complete the file operation commands. To use the vi editor correctly, you must be proficient in switching between the two modes.

vi command

vi command is in UNIX operating systems and UNIX-like operating systems The most versatile full-screen plain text editor. The vi editor in Linux is called vim, which is an enhanced version of vi (vi Improved). It is fully compatible with the vi editor and implements many enhanced functions.

vi editor supports edit mode and command mode. In edit mode, you can complete text editing functions, and in command mode, you can complete file operation commands. To use the vi editor correctly, you must be proficient in both. Mode switching. By default, the vi editor automatically enters command mode after opening it. Use the "esc" key to switch from edit mode to command mode, and use the "A", "a", "O", "o", "I", and "i" keys to switch from command mode to edit mode.

The vi editor provides a wealth of built-in commands. Some built-in commands can be completed using keyboard key combinations, and some built-in commands need to be entered starting with a colon ":". Commonly used built-in commands are as follows:

Syntax

##vi(options)(parameters)

Options

Parameters

File list: Specify the Edited file list. Use spaces to separate multiple files.

Knowledge expansion

The vi editor has three working modes: command mode, input mode and ex escape mode. Through corresponding commands or operations, conversion can be performed between these three working modes.

Command mode

Enter the command vi after the Shell prompt to enter the vi editor and be in vi command mode. At this time, any characters entered from the keyboard are interpreted as editing commands. For example, a (append) represents an append command, i (insert) represents an insert command, x represents a delete character command, etc. If the entered character is not a legal command of vi, the machine will sound an "alarm sound" and the cursor will not move. In addition, the characters entered in command mode (i.e. vi command) are not displayed on the screen. For example, if you enter i, there will be no change on the screen, but by executing the i command, the working mode of the editor will change: by command mode Change to input mode.

Input method

By inputting vi’s insert command (i), append command (a), open command (o), replace command (s), and modify command (c) or replace the command (r) to enter the input mode from the command mode. In input mode, all characters entered from the keyboard are inserted into the buffer being edited and treated as the text of the file. After entering the input mode, all the visible characters entered are displayed on the screen, but the editing commands no longer work and only appear as ordinary letters. For example, if you enter the letter i in command mode, enter the input mode, and then enter i again, a letter i will be added to the corresponding cursor on the screen.

The way to return to the command mode from the input mode is to press the Esc key. If you are already in command mode, pressing the Esc key will make a "beep" sound. In order to ensure that the vi command that the user wants to execute is entered in command mode, you may wish to press the Esc key a few more times and enter the command after hearing the beep.

ex escape method

The functions of vi and ex editor are the same, the main difference between them is the user interface. In vi, commands are usually single letters, such as a, x, r, etc. In ex, the command is a command line that ends with the Enter; key. vi has a dedicated "escape" command that provides access to many line-oriented ex commands. To use ex escape mode, enter a colon (:). As with the ex command prompt, the colon appears on the status line (usually the bottom line of the screen). Press the interrupt key (usually the Del key) to terminate the executing command. Most file management commands are executed in ex escape mode (for example, reading a file, writing the contents of the edit buffer to a file, etc.). After the escape command is executed, it automatically returns to the command mode. For example:

will replace all uppercase I's with lowercase i's from the first line of the file to the end of the file ($).

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