How to use the command 'vipe' (with examples)

The vipe command is a useful tool for anyone working in a UNIX environment who needs the flexibility of a text editor in the middle of a pipeline. Part of the moreutils package, vipe allows users to pause the stream of data flowing through pipes to make interactive edits before continuing with the next steps in the pipeline. This makes vipe incredibly valuable for those who need to tweak or inspect intermediate data without breaking the pipeline’s continuity.

Use case 1: Edit the output of command1 before piping it into command2

Code:

command1 | vipe | command2

Motivation:

In many instances, while processing data in a pipeline, you might encounter scenarios where the output of one command needs slight manual adjustments before passing it to the next stage. Automating this process can sometimes be challenging, especially if the transformation required is highly context-specific or involves complex logic that could be cumbersome to script. For example, when processing logs or configuring files where small, context-specific edits are necessary, vipe offers a seamless way to intervene manually without disrupting the entire automated process.

Explanation:

• command1: The command that generates the initial output. This could be any command that produces data you wish to modify, such as grep, awk, or find.

• vipe: This command reads the input coming from command1 and opens it in the default text editor, allowing you to make any changes manually before proceeding.

• command2: The command that receives the modified data from the editor. For instance, this could be sort, uniq, xargs, or any other utility that performs operations on the output data.

Example output:

Imagine you are listing files whose names contain “2023” but wish to exclude certain entries manually. Once you’ve made your selection edits inside the editor launched by vipe, only the desired file names continue in the pipeline for further processing in command2.

Use case 2: Buffer the output of command1 in a temporary file with the specified file extension in order to aid syntax highlighting

Code:

command1 | vipe --suffix json | command2

Motivation:

When working with data formats like JSON, XML, or HTML, syntax highlighting can significantly improve readability and help you to discern errors or anomalies in the data more quickly. By specifying the file extension, vipe uses your text editor’s syntax highlighting capabilities to enhance the editing experience, making it easier and more efficient to manipulate data. This is particularly beneficial for developers who need to inspect or modify configuration files or API responses within a pipeline.

Explanation:

• command1: Generates output that needs inspection, such as curl fetching JSON data from an API.

• vipe --suffix json: The --suffix json option tells vipe to create a temporary file with a .json extension, enabling JSON syntax highlighting in supported text editors.

• command2: Receives the highlighted and possibly edited data. This command might further process or analyze the data, depending on your needs, such as jq or another JSON parsing tool.

Example output:

Consider a case where you fetch JSON data and need to remove a few entries or adjust a value manually. Using syntax highlighting, you identify and perform these edits directly within vipe, providing greater precision and understanding before passing along the data to command2.

Use case 3: Use the specified text editor

Code:

command1 | EDITOR=vim vipe | command2

Motivation:

Different users have different text editor preferences based on their familiarity, keyboard shortcuts, or specific feature sets they find useful. Availability of features like syntax highlighting, multiple panes, or powerful search-and-replace capabilities often dictate the choice of editor. By allowing the specification of the editor, vipe caters to diverse editing preferences, ensuring that users can leverage their tool of choice for maximum productivity when intervening in a pipeline process.

Explanation:

• command1: The command output requiring editing, which could be anything from data queries to system logs.

• EDITOR=vim vipe: Here, the EDITOR=vim environment variable sets vim as the editor to be used by vipe. Users might choose vim, nano, emacs, or another preferred editor.

• command2: Receives the polished output after human intervention using the specified editor. This is often another shell command that continues or concludes processing the edited data.

Example output:

Imagine you’re editing raw SQL query outputs where specific rows must be added or removed. Utilizing vim through vipe, you can efficiently perform these edits using familiar commands like dd to delete lines or :wq to save and continue, after which the refined output passes seamlessly into command2.

Conclusion:

The vipe command is a versatile and powerful tool for anyone operating within UNIX systems, adding an invaluable flexibility to command pipelines. It bridges the divide between automated and manual processes, allowing for greater precision and customization with minimal interruption. Whether you need to manually intervene in data processing, benefit from syntax highlighting, or employ a specific text editor, vipe empowers you to do so efficiently within structured, linear workflows.