Capturing Output Of Vim Internal Commands To Buffers

The versatility of Vim, a powerful text editor, extends beyond simple text manipulation, offering a robust system for managing windows and buffers. Understanding how to capture the output of internal Vim commands into buffers can significantly enhance a user’s workflow. This article delves into the intricacies of window management, buffer usage, and how to effectively capture command outputs within Vim, providing practical insights for both novice and experienced users.

Key Takeaways

  • Vim’s window management allows for efficient navigation and organization of multiple files within a single session.
  • Buffers in Vim are not merely files in memory; they can be leveraged for advanced editing tasks and managing hidden content.
  • Executing commands across multiple buffers and integrating autocommands can automate repetitive tasks and streamline editing processes.
  • Redirecting command output to buffers in Vim can be accomplished with specific command modifiers and techniques for output management.
  • Customizing Vim with scripts, plugins, and command aliases can transform the editor into a more powerful and personalized tool.

Understanding Vim’s Window Management

The Basics of Window Commands

Vim’s window management system is a powerful feature that allows users to view and edit multiple files or different parts of a file simultaneously. Understanding the basic window commands is essential for efficient navigation and editing within Vim. Here’s a quick reference to some fundamental window commands:

  • :split or CTRL-W s – Split the current window horizontally.
  • :vsplit or CTRL-W v – Split the current window vertically.
  • CTRL-W w – Cycle through windows.
  • CTRL-W q – Close the current window.

Remember, the behavior of new windows can be influenced by the ‘splitbelow’ and ‘splitright’ options, ensuring a consistent layout as per your preferences.

Creating and managing windows in Vim involves understanding the constraints of your workspace. For instance, every window requires a minimum amount of screen space, governed by the ‘winminheight’ and ‘winminwidth’ options. Attempting to create a window when there is insufficient room will result in failure. To navigate between windows, you can use CTRL-W W for moving to the window above or left, and CTRL-W t and CTRL-W b for jumping to the top-left or bottom-right windows, respectively.

Customizing Window Behavior

Customizing the behavior of windows in Vim allows for a more efficient and personalized editing experience. Vim’s window management is highly configurable, enabling users to set minimum dimensions and control how windows are resized and arranged. For instance, the ‘winminheight’ and ‘winminwidth’ options dictate the smallest possible size of a window, ensuring that it never becomes too small to be useful.

When adjusting window sizes, Vim provides commands to equalize the dimensions of all windows. The CTRL-W = command makes all windows almost equally high and wide, while respecting the ‘winheight’ and ‘winwidth’ settings for the current window. Windows with ‘winfixheight’ or ‘winfixwidth’ set will maintain their respective sizes. For more granular control, vertical wincmd = and horizontal wincmd = can be used to equalize window heights and widths separately.

Vim’s flexibility extends to window layout changes. Using commands like CTRL-W K and CTRL-W H, users can swiftly alter the arrangement of windows from vertical to horizontal splits and vice versa, optimizing the workspace for the task at hand.

It’s important to note that certain autocommands, such as Buf/Win Enter/Leave, are not triggered when new windows are opened. This behavior ensures that these events are only processed when the windows are actively used, which can improve performance when dealing with multiple files.

Navigating Between Windows

Once you’re comfortable with managing multiple windows in Vim, navigating between them efficiently becomes crucial. Vim offers a variety of commands to move the cursor between windows, each catering to different layouts and user preferences. For instance, to move left or right between windows, you can use CTRL-W h and CTRL-W l respectively. Similarly, CTRL-W j and CTRL-W k will move the cursor down and up. These commands are intuitive as they correspond to the h,j,k,l keys used for cursor movement in normal mode.

For more advanced window navigation, Vim provides commands to rotate and exchange windows. CTRL-W r rotates windows in the current row or column, while CTRL-W x exchanges the current window with the next or previous one. To quickly jump to the first or last window, use CTRL-W t for the top-left window and CTRL-W b for the bottom-right window. Remembering these commands can significantly speed up your workflow.

Vim’s window navigation commands are not just about moving from one window to another; they’re about maintaining a flow in your editing process. Mastering these commands allows you to keep your hands on the keyboard and your focus on the code.

Leveraging Buffers in Vim

Buffer Basics and Management

In Vim, buffers are central to managing the text you’re working with. A buffer can be thought of as a container for the contents of a file that you have opened. Buffers can be visible or hidden, with hidden buffers allowing you to keep files open without displaying them in a window. This is particularly useful for multitasking and preserving the state of your work.

Vim offers several options to customize buffer behavior, such as ‘bufhidden’, which determines what happens when a buffer is no longer displayed, and ‘buftype’, which specifies the type of buffer. Additionally, ‘swapfile’ and ‘buflisted’ are options that control whether a buffer will have a swap file and if it should show up in the buffer list, respectively.

Understanding and effectively managing buffers is crucial for efficient Vim usage. It allows for seamless navigation and editing across multiple files.

Here’s a quick reference for buffer-related commands:

  • :ls or :buffers – List all buffers.
  • :bnext or :bn – Go to the next buffer.
  • :bprev or :bp – Go to the previous buffer.
  • :bdelete or :bd – Delete a buffer (close a file).

Remember that Vim treats all open files as buffers, whether they are active, hidden, or inactive. An active buffer is one that is currently displayed in a window, while a hidden buffer is not displayed but still loaded in memory.

Working with Hidden Buffers

In Vim, hidden buffers are a powerful feature that allows you to keep files loaded in memory without displaying them in a window. This is particularly useful when you need to switch between files quickly without the overhead of reloading them each time. To work with hidden buffers, you can use the :buffer-! command, which, when combined with the ‘hidden’ option, keeps abandoned buffers in memory.

To toggle the visibility of a hidden buffer, you can simply edit it with any command or remove it using the :bdelete command. The ‘bufhidden’ option provides additional control, allowing you to specify behavior for individual buffers:

  • <empty>: Inherits the global ‘hidden’ setting.
  • hide: Hides the buffer, even if the global ‘hidden’ is not set.
  • unload: Unloads the buffer instead of hiding it, regardless of the ‘hidden’ setting.
  • delete: Deletes the buffer.

It’s important to note that hidden buffers are still part of Vim’s buffer list and can be navigated to, even if they are not currently visible in a window.

Buffer-Related Functions and Commands

Vim’s versatility extends to how it handles buffers, which are essentially the in-memory text storage areas. Buffers can be much more than just containers for file contents; they can serve specialized purposes and be manipulated through various functions and commands. For instance, the :ls or :buffers command lists all buffers, indicating their status—whether they are active, hidden, or in a special state like ‘quickfix’ or ‘help’.

Buffer management is crucial for efficient workflow in Vim. Commands such as :bnext and :bprevious allow for quick navigation between buffers. Setting buffer-specific options like 'bufhidden' and 'buftype' can customize how buffers behave when they are not displayed. Additionally, the 'swapfile' and 'buflisted' options determine whether a buffer will have a swap file and if it should appear in the buffer list, respectively.

Vim’s buffer commands are powerful tools that can significantly enhance text editing efficiency.

Understanding and utilizing these buffer-related functions and commands can greatly streamline your editing process, especially when working with multiple files or complex projects.

Advanced Window and Buffer Operations

Executing Commands Across Multiple Buffers

Vim’s ability to execute commands across multiple buffers is a powerful feature for batch processing or consistent modifications. The :bufdo command is central to this functionality, allowing users to apply a command to each buffer in the buffer list. This can be particularly useful when you need to perform repetitive tasks, such as search and replace operations, across several files.

The execution of :bufdo is sequential, starting with the first buffer and proceeding to the next until all eligible buffers have been processed. It’s important to note that unlisted buffers are skipped and the process will halt if an error is encountered in any buffer.

Here is a basic sequence of steps to use :bufdo:

  1. Open the buffers you want to work with.
  2. Use :bufdo {cmd} to execute your command across all listed buffers.
  3. Review the changes and save them with :wa (write all).

Remember that :bufdo must not be used with commands that add or delete buffers, as this could disrupt the sequence of execution. Additionally, the ‘readonly’ flag is maintained across buffer edits, which differs from the behavior of the :edit command.

Integrating Autocommands with Buffers

Vim’s autocommands provide a powerful way to automate tasks in response to various events. By integrating autocommands with buffer operations, users can create dynamic workflows that react to changes in the buffer environment. Autocommands can be tailored to specific file types or buffer states, enhancing the editing experience.

For instance, you might want to set up an autocommand to automatically format code when a buffer is saved, or to trigger a custom script when entering a buffer with a particular file extension. Here’s a simple example of an autocommand that echoes a message after displaying a PNG file:

autocmd "PostDisplay" ".*png" "echo 'this is a png file'"

Autocommands can be chained with buffer commands to perform complex operations. They can be especially useful when combined with plugins or scripts that extend Vim’s functionality, such as asynchronous buffer completion mechanisms.

Window Resizing and Arrangement Techniques

Mastering window resizing and arrangement in Vim enhances the user experience and productivity. Vim offers a variety of commands to adjust window dimensions, catering to the needs of different workflows. For instance, CTRL-W > and CTRL-W < are used to increase or decrease the window width, respectively. Similarly, CTRL-W + and CTRL-W - adjust the window height.

To apply a uniform size to all windows, the command CTRL-W = can be used, which respects the winheight and winwidth settings for the current window. However, windows with winfixheight or winfixwidth set will maintain their dimensions. For more granular control, :resize followed by a number can set the height explicitly, and :vertical resize does the same for width.

Vim’s flexibility in window management is evident through its commands that allow quick adjustments and fine-tuning of the editing environment.

When dealing with multiple windows, it’s often necessary to resize them according to specific requirements. Here’s a quick reference for some common resizing commands:

Command Action
CTRL-W > Increase window width
CTRL-W < Decrease window width
CTRL-W + Increase window height
CTRL-W - Decrease window height
CTRL-W _ Maximize window height

Remember that window resizing can also be achieved through mouse interactions if Vim is compiled with mouse support and the ‘mouse’ option is enabled. This intuitive method involves dragging the status line or vertical separator to adjust the window size.

Capturing Command Outputs in Vim

Redirecting Output to Vim Buffers

In Vim, the ability to redirect the output of internal commands to buffers can significantly enhance your workflow. Capturing command outputs allows for easy review and manipulation of data. This can be particularly useful when dealing with the results of searches, compilations, or any other command that generates output.

To redirect output to a buffer, you can use the :redir command followed by the > operator and the target buffer. For example, :redir > buffername will start redirecting command output to the buffer named ‘buffername’. To stop redirection, use :redir END.

Redirection is not limited to named buffers. You can also redirect output to a new unnamed buffer, which can be useful for temporary data that does not require saving.

Here is a simple list of steps to capture the output of a command into a buffer:

  1. Open a new buffer (or use an existing one).
  2. Execute the :redir command to start redirection.
  3. Run the Vim command whose output you want to capture.
  4. Use :redir END to stop the redirection process.
  5. Review the captured output in the buffer.

Using Command Modifiers for Output Management

Vim’s versatility extends to how it handles the output of internal commands. Command modifiers can be used to redirect this output to different destinations, including buffers. This is particularly useful when you want to capture the results of a command for further analysis or manipulation without cluttering your main editing space.

For instance, you can use the :redir command to start capturing command output, and :redir END to stop. Here’s a simple workflow:

  1. :redir > buffername to start redirecting output to a buffer.
  2. Execute the desired Vim commands.
  3. :redir END to stop capturing and save the output in the specified buffer.

Remember, the buffer must be created beforehand or Vim will throw an error.

Autocommands can also play a pivotal role in output management. They allow you to automate tasks upon certain events. For example, the BufWritePost event can be used to capture the buffer content right after it’s saved. Below is a list of some autocommand events related to writing buffers:

  • BufWriteCmd
  • BufWritePre
  • BufWritePost

Understanding and utilizing these autocommands can significantly streamline your workflow in Vim.

Practical Examples of Output Capture

Vim’s versatility extends to capturing the output of internal commands, which can be redirected into buffers for further manipulation or reference. One practical application is capturing the output of a plugin’s commands. For instance, a user might want to grab images from a webcam using vgrabbj and display them in Vim, or even save a screenshot of the current Vim session.

To illustrate, consider the following steps to capture and display webcam images:

  • Use the fim command with the pread option to grab an image.
  • Reload the buffer to display the new image.
  • Optionally, save the image to a file using fbgrab if running in framebuffer mode.

Vim’s ability to execute and capture the results of external commands opens up a myriad of possibilities for automation and integration with other tools.

Another example involves recording and executing sequences of commands. Users can start and stop recording with recording 'start' and recording 'stop', respectively. Executing recording 'dump' will display the recorded commands, which can then be executed with recording 'execute'. This feature is particularly useful for automating repetitive tasks within Vim.

Customizing and Extending Vim Functionality

Creating and Managing Command Aliases

In the world of Vim, command aliases are powerful shortcuts that can significantly speed up your workflow. They can be redefined with the alias command or deleted with the unalias command, allowing for a high degree of customization. Default aliases are typically loaded at startup, which can be reviewed and modified as needed.

Creating a new alias involves assigning a user-defined command or sequence of commands to an identifier. This can be done with the alias command followed by the identifier and the command you wish to assign. For example, to create an alias that toggles verbosity, you might use:

alias "toggleVerbosity" "_display_console=1-_display_console;i:fresh=1;redisplay"

To manage your aliases effectively, consider the following steps:

  • List existing aliases: Simply use the alias command without arguments to see all current aliases.
  • Set or create a new alias: Provide the identifier and the command to the alias command.
  • Remove an alias: Use the unalias command followed by the identifier of the alias you wish to delete.

Remember, aliases are not just about saving keystrokes; they encapsulate complex command sequences into manageable and memorable shortcuts.

Implementing Autocompletion and Command History

Vim’s extensibility is one of its most powerful features, allowing users to tailor the editor to their specific workflow needs. Scripts and plugins can significantly enhance Vim’s functionality, providing custom solutions for editing, navigating, and managing files. For instance, plugins can introduce new commands, modify existing behavior, or add complex features like code linting and syntax highlighting.

To manage plugins effectively, users should familiarize themselves with plugin managers such as Vim-Plug, Pathogen, or Dein.vim. These tools simplify the process of installing, updating, and removing plugins. Here’s a basic workflow using Vim-Plug:

  • Install Vim-Plug by downloading the plug.vim file and placing it in the autoload directory.
  • Add plugin declarations to your .vimrc file using the Plug command.
  • Run :PlugInstall to install the plugins.
  • Use :PlugUpdate to update and :PlugClean to remove unused plugins.

Vim scripts, on the other hand, are often used for more specific tasks or to automate repetitive actions. They can be written directly in Vim’s scripting language, Vimscript, and executed with the :source command.

When customizing Vim, it’s important to test changes in a controlled environment to avoid disrupting your workflow. Creating a separate vimrc file for experimentation or using Vim’s built-in sandbox mode can be helpful strategies.

Enhancing Vim with Scripts and Plugins

Vim’s extensibility is one of its most powerful features, allowing users to tailor the editor to their specific needs. Plugins and scripts can significantly enhance Vim’s functionality, ranging from simple syntax highlighting to complex code manipulation tools. The Vim online platform is a treasure trove for such enhancements, where users can upload and share their own scripts.

To get started with scripts and plugins, one should familiarize themselves with the types of scripts available. For instance, syntax scripts enable syntax highlighting, which is essential for readability and error detection in code. Color scheme scripts, on the other hand, allow for customization of the editor’s aesthetic, making long coding sessions easier on the eyes.

Incorporating these tools into your Vim setup can streamline your workflow and increase productivity. Here’s a simple guide to managing scripts and plugins in Vim:

  • Install a plugin manager like Pathogen or Vundle.
  • Search for plugins or scripts on Vim online or GitHub.
  • Install the desired plugins using the plugin manager’s commands.
  • Configure your .vimrc file to set up the plugins according to your preferences.

Remember, while plugins can offer powerful features, it’s important to evaluate them for security and maintainability. Not all scripts are created equal, and some may introduce more complexity than benefit.


Throughout this article, we’ve explored the intricacies of capturing the output of Vim’s internal commands into buffers, a technique that enhances the flexibility and power of working with this venerable text editor. From the basics of opening and managing windows to the more advanced topics like manipulating hidden buffers and utilizing autocommands, we’ve covered a range of methods to streamline your workflow in Vim. Whether you’re a seasoned Vim user or new to the world of text editing, the ability to redirect command outputs to buffers is a valuable skill that can significantly improve your efficiency. Remember, the true power of Vim lies in its customizability and the ability to tailor the environment to your needs, and mastering these commands is a step towards unlocking that potential.

Frequently Asked Questions

How can I start Vim with multiple windows?

By default, Vim starts with one window. To start Vim with multiple windows, you can use the ‘-o’ or ‘-O’ options followed by the files you want to open, or use ‘:split’ and ‘:vsplit’ commands after opening Vim to create new windows.

What is the difference between buffers and windows in Vim?

In Vim, a buffer is a file loaded into memory for editing, while a window is a viewport that displays a buffer. You can have multiple windows showing different parts or even the same part of a buffer.

How do I navigate between different windows in Vim?

You can navigate between windows in Vim using the ‘CTRL-W’ followed by a navigation key (h, j, k, l) to move left, down, up, or right, respectively. You can also use ‘CTRL-W w’ to cycle through windows.

Can I execute a command across all buffers in Vim?

Yes, you can execute a command across all buffers by using the ‘:bufdo’ command followed by the command you wish to execute. For example, ‘:bufdo w’ will save all open buffers.

How do I resize windows in Vim?

You can resize windows in Vim by using the ‘:resize’ command followed by a number to change the height, or ‘:vertical resize’ followed by a number to change the width. You can also use ‘CTRL-W =’ to make all windows equal size.

What are autocommands in Vim and how do I use them?

Autocommands in Vim are a way to execute commands automatically in response to certain events, such as opening or closing a buffer. You can use them by defining an event, a pattern to match files or buffers, and the command to execute, like ‘:autocmd BufRead *.txt echo “Reading a text file”‘.

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