Vim tutorial-2: Tab and Window, Buffer and File

Apr. 12, 2021

I will introduce the concept of tab and window, buffer and file, and their relationships.

Preface

Buffer, file, window, tab are the most basic things in an editor, but they are easily ignored by many users. Fig. 1 summarizes the relationships among tabs and windows, buffers and files in Vim.

File is the file on the disk.
Buffer is the temporary object created by Vim. Users can use buffer to interact with files.
Window is to display the content in buffer. Each window can only be binded to one buffer, but the same buffer can be displayed though several windows.
Tab is the collection of all windows on the same full screen (here full screen means the screen occupied by Vim). In one tab, we can generate windows though splitting (vertical or horizontal).

Figure 1. Demonstration of the tabs and windows, buffers and files in Vim.

Buffer and File

File is the easiest concept to understand here, which is the file on the disk. The core task of an editor is to read the content of a file, edit it and save it back to the disk. A basic computer hardware knowledge is that the read and write to a disk is super-slow compared to the main memory. So most of the software will create a temporary object in the main memory and write the content to the disk when the job is done. In Vim, buffer is the that object.

You input :edit filename;
Vim will first create a buffer called filename. Then, Vim will see if filename exists. If it exists, Vim will load the content in the disk to the buffer and you can edit it. Otherwise, Vim will do nothing, and you can edit an empty buffer.
After editing, you can use :write to write to the disk. If the file already exists on the disk, Vim will replace the content with the new one. Otherwise, Vim will create a new file on the disk and write the content to it.

There are something you need to be careful.

Buffer is not necessary to be binded with a file on the disk. Actually, some plugins use buffer to present other things, like file tree, searching result, terminals and so on.
Vim will not synchronize the content of buffer and the disk until you explicitly call :write or :w. So the two commands that Vim used to interact with file on the disk is :write and :edit, while all other editing commands is for the user to interact with the buffer.

Tab and window

Creation

When you enter Vim though vim command, you will have one window in one tab. Then you can use :split to split the window horizontally (:vsplit for vertical splitting), and you will have several windows (like Fig. 1) in one tab.

To create new tabs, you can use :tabnew to create more tabs, and you can split windows in the new tabs.

To jump to other window, the most basic key-mappings are <Ctrl-w>h, <Ctrl-w>j, <Ctrl-w>k and <Ctrl-w>l. It will jump to the adjacent window relative to the current cursor position. For example, if you press <Ctrl-w>l in Win-1 in Fig. 1, which window it will jump to? If your cursor is at the upper half of Win-1, it will jump to Win-2. Otherwise, it will jump to Win-3.

If there are too many windows, a useful plugin is vim-choosewin. It will generate alphabetic characters for each window, and you can jump to the target window by pressing the corresponding character. Another useful function of this plugin is that you can swap the buffers of two windows.

Sometimes, you might want to maximize one window. For example, you opened the documentation in a small splitting window, which is inconvenient for reading, so you want to maximize it. After that, you want to restore to the previous window layout. There are many plugins out there for this, and I found a stable one, vim-maximizer.

To navigate the tabs, you can use :tabnext and :tabprevious, and I mapping these two commands to ]t and [t.

To customize the name of the tab, you can use the plugin taboo.vim.

Other things

In one Vim process, you can only have one active cursor, so you can only have one current tab and current window.
The content of one buffer can be displayed in several windows in different tabs. You do not need to worry about the synchronization, because you can only have one current tab and window.
It is a good habit to restrict the maximum line length of your code (there are many formatting plugins out there), then your code will not be hidden when you vertically split the tab.

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