Скачать или смотреть Grep for Process Path with a Variable Three-Digit Number in Linux

Learn how to use the `grep` command in Linux to search process paths that include a variable three-digit number. Follow this guide for effective searching!
---
This video is based on the question https://stackoverflow.com/q/63489685/ asked by the user 'NKumar' ( https://stackoverflow.com/u/5532090/ ) and on the answer https://stackoverflow.com/a/63489727/ provided by the user 'Cornholio' ( https://stackoverflow.com/u/10415029/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

Visit these links for original content and any more details, such as alternate solutions, latest updates/developments on topic, comments, revision history etc. For example, the original title of the Question was: grep for path in process(ps) containing number

Also, Content (except music) licensed under CC BY-SA https://meta.stackexchange.com/help/l...
The original Question post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license, and the original Answer post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license.

If anything seems off to you, please feel free to write me at vlogize [AT] gmail [DOT] com.
---
Mastering grep to Find Process Paths with Variable Numbers

If you are a Linux user, you likely find yourself needing to locate specific running processes from time to time. A common scenario arises when the process path contains a variable number, such as a three-digit identifier that changes frequently. In this guide, we will explore how to use the grep command effectively to search for process paths that include a three-digit number.

The Challenge: Grep for a Process Path

Imagine you are trying to locate a specific process running on your server, and the path looks something like this:

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

In this case, the part of the path we want to grep for is "psd_folr/rcerr-m-deve-udf-172/bin/magt queue", but the number 172 could change and could be any three-digit number.

Understanding the Regular Expression Issues

When trying to use grep for this purpose, you may have attempted the following command:

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

This command does not yield any results due to several issues in the regular expression used:

Apostrophes: The apostrophes in your command do not add any syntactical value to grep.

Caret (^): This symbol denotes the start of a line, which is irrelevant when looking for a number within a process output.

Dollar ($): Similar to the caret, this indicates the end of a line, which does not apply here either.

Single Digit Match: The expression [0-9] only matches a single digit, which means it cannot capture three digits as required.

Crafting the Correct Regular Expression

To successfully locate the process with a three-digit number, your regular expression needs some modifications. Here’s what you can do:

Recommended Changes:

Match Multiple Digits: Use -[0-9]+ / to match one or more digits or -[0-9]{3}/ to ensure exactly three digits are matched.

Use Extended Regular Expressions: Activate this feature with the -E flag for grep, but if you choose not to use it, ensure to escape special characters like + or {n}.

Updated Command

The following command should work perfectly for your requirements:

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

Additional Tips:

Check Your Grep Version: Ensure that you are using a version of grep that supports the -E flag.

Experiment: If you're uncertain about the output, test different patterns to validate that your command meets the criteria.

Conclusion

Finding a process in Linux that includes a variable three-digit number does not have to be complex. By using the correct regular expression with grep and keeping the suggestions outlined above in mind, you can streamline your process management. Whether you're a beginner or an experienced user, mastering these commands will make your Linux experience much more efficient.

So the next time you're searching for that errant process, remember to construct your grep command thoughtfully! Happy grepping!