Скачать или смотреть How to Properly Read Property File Values in Bash Without Truncation

Learn how to read property file values correctly in Bash without losing any part of the value due to truncation caused by the '=' sign.
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This video is based on the question https://stackoverflow.com/q/62732667/ asked by the user 'Sreenivas Ponnadi' ( https://stackoverflow.com/u/12951317/ ) and on the answer https://stackoverflow.com/a/62732704/ provided by the user 'wjandrea' ( https://stackoverflow.com/u/4518341/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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Understanding the Problem: Reading Property File Values in Bash

When working with property files in Bash, it's common to encounter issues while trying to extract values associated with keys. A common scenario is when the values contain multiple equals signs (=), leading to unintended truncation of the value. If you're not careful, you might only retrieve a part of the desired value, potentially missing critical information.

For instance, consider a line in a property file:

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Using a standard method to read this property may result in the extraction stopping at the first equal sign, leading to incomplete data. This problem is elegantly illustrated by the error encountered using this Bash command:

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

The command above attempts to cut out the second portion of the line (i.e., the value), but it stops processing at the first equal sign, effectively truncating the output.

A Clear Solution: Using cut Effectively

To overcome this truncation issue, we can modify our command to ensure that we capture the entire value from the property file. Here’s how you can do it:

Modify the cut Command

Instead of using -f2 which only retrieves the second field (the part right after the first equal sign), we will adjust it to retrieve everything after the first equal sign to the end of the line.

The Correct Command

You can do this by using:

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Breakdown of the Command

cat configReplace.properties: This command reads the content of your properties file.

grep "$key": This filters the output to find the specific line containing your desired key.

cut d'=' -f2-: Here, we use -f2 which tells cut to get everything starting from the second field through to the end of the line. This way, all equals signs in the value will no longer cause truncation.

Example in Practice

If you were to run the modified command with the previously mentioned entry, it would yield the full URL with all parameters intact:

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Conclusion

By adjusting the way we use cut in Bash, we can seamlessly read property file values without the risk of truncation. This small tweak ensures that we capture the complete value associated with a key, allowing for more accurate and complete data manipulation in our shell scripts.

Next time you find yourself struggling with property file values in Bash, remember this simple yet effective solution! Happy scripting!