Comprehensive Guide on Using 'linkchecker' (with examples)

The linkchecker command-line tool is a valuable resource for web developers and administrators who need to ensure the integrity of links within their websites. It checks HTML documents and websites for broken or invalid links, providing a seamless way to maintain the credibility and user experience of a site. By comparing links against a database of valid URLs, it helps identify and rectify errors that may lead to dead-end pages, thus enhancing the reliability of the website.

Use case 1: Finding broken links on a website

Code:

linkchecker https://example.com/

Motivation:

The primary motivation for using this command is to quickly identify broken links on a website. Broken links lead to a poor user experience and can negatively affect a website’s search engine ranking. Regularly checking for such issues can help in maintaining a professional and user-friendly website environment.

Explanation:

• linkchecker: This is the command used to initiate the checking process.
• https://example.com/: This is the target website URL on which the link check is performed. The tool scans the entire site to ensure that all internal links are functioning correctly.

Example Output:

URL        | Result      | Error Message               
---------- | ----------- | ---------------------------
/page1     | OK          |                            
/page2     | Broken link | 404 Not Found              
/external  | OK          |                            

Use case 2: Checking URLs that point to external domains

Code:

linkchecker --check-extern https://example.com/

Motivation:

Websites often link to external sources for references or additional information. These external links are beyond the control of the website owner, making it important to verify their status regularly. This command is used to ensure that external links are still active and direct users to the intended resources.

Explanation:

• linkchecker: Initiates the link verification process.
• --check-extern: This option tells the tool to include checks for external links. By default, only internal links are checked.
• https://example.com/: The website URL to begin the link-checking procedure.

Example Output:

URL                   | Result      | Error Message               
--------------------- | ----------- | ---------------------------
/internal-link        | OK          |                            
https://otherdomain.com | OK          |                            
https://external.com/dead-link | Broken link | 404 Not Found    

Use case 3: Ignoring URLs that match a specific regular expression

Code:

linkchecker --ignore-url regular_expression https://example.com/

Motivation:

In some cases, you may want to exclude certain links from the check, such as those that are known to be obsolete or those with specific patterns that should not trigger alerts. This is useful for filtering out predictable or irrelevant links, thus reducing the noise in the results.

Explanation:

• linkchecker: Command to perform a link check.
• --ignore-url regular_expression: This option specifies a pattern to exclude certain links. The regular expression will match URLs that should not be checked.
• https://example.com/: The URL where the link checking will be initiated.

Example Output:

URL        | Result      | Error Message               
---------- | ----------- | ---------------------------
/page1     | OK          |                            
/ignored   | Skipped     | Ignored by pattern         
/external  | OK          |                            

Use case 4: Outputting results to a CSV file

Code:

linkchecker --file-output csv/path/to/file https://example.com/

Motivation:

Exporting the results to a CSV file is especially beneficial for documentation and analysis purposes. It facilitates easy sharing and further processing of data in spreadsheet programs, allowing team members to review and prioritize issues effectively.

Explanation:

• linkchecker: Executes the link check.
• --file-output csv/path/to/file: Specifies the format (CSV in this case) and the path where the output should be saved. This makes it easier to distribute and archive the results.
• https://example.com/: The URL to check for broken links.

Example Output in CSV:

URL, Result, Error Message
/page1, OK, 
/page2, Broken link, 404 Not Found
/ignored, Skipped, Ignored by pattern

Conclusion:

The linkchecker command is an essential tool for maintaining the integrity of a website’s links. Each use case demonstrates a unique application of the command, providing a robust solution for web administrators. Whether you are ensuring internal and external link functionality, excluding certain URLs, or generating reports, linkchecker offers comprehensive support to enhance website reliability and user experience.