Скачать или смотреть How to Extract Values from Specific Tags in XML Using xmllint

A step-by-step guide on how to search for a specific term within XML and extract its value using `xmllint` and Bash scripting.
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Extract Values from Specific Tags in XML Using xmllint

When working with XML data, we often face the challenge of retrieving specific information based on certain criteria. In this guide, we'll focus on a common task: searching for a term within a specific tag and extracting its associated value. We'll use xmllint, a command-line tool for parsing XML files, and some straightforward Bash scripting to achieve our goals.

The Problem

Imagine you have an XML file containing multiple articles. Each article has several tags, such as the title, author, publication date, and a reference number. You want to search for an article based on its reference number and then retrieve the title of that specific article. This can become tricky if you have a large XML structure and need to ensure accurate searching.

Here's a snippet of what our XML data looks like:

[[See Video to Reveal this Text or Code Snippet]]

The Solution

To extract the title based on a specific reference number, we can create a simple Bash script. Here's how it works:

Script Breakdown

Define Variables:

ref_no: This variable will hold the reference number you want to search for.

src_xml: This variable references the XML file you wish to parse.

Use xmllint to Query XML:

We'll formulate an XPath expression that targets the title of the article based on the reference number.

Here is the complete script:

[[See Video to Reveal this Text or Code Snippet]]

How to Use This Script

Save the Script: Create a new file (e.g., extract_title.sh) and copy the code above into it.

Make it Executable: Run chmod + x extract_title.sh to make the script executable.

Run the Script:

You can run the script by passing the reference number as an argument. For example:

[[See Video to Reveal this Text or Code Snippet]]

The output will show the reference number along with the corresponding title:

[[See Video to Reveal this Text or Code Snippet]]

Variations for Different Reference Types

If your reference number is a string (e.g., "a10001"), you will need a small adjustment. Here’s what the modified script would look like:

[[See Video to Reveal this Text or Code Snippet]]

Output Example

Just like before, by running:

[[See Video to Reveal this Text or Code Snippet]]

You will receive an output like:

[[See Video to Reveal this Text or Code Snippet]]

Conclusion

With just a few lines of Bash scripting and the powerful xmllint tool, we've successfully built a method to search for specific terms in XML documents and extract their values based on set criteria. This approach not only streamlines the process of interacting with XML data but also allows for flexibility in managing different data structures.

Feel free to experiment with the script to fit your XML structure, and happy scripting!