regex

The blog post explains how to convert `git log` output into a structured CSV file using `awk` and regular expressions. It covers the initial setup of Git and `awk` on Linux, customizing `git log` output, and detailed `awk` scripting examples for formatting and refining the data, ensuring its integrity in CSV format. The tutorial demonstrates both basic and advanced uses of `awk` for effective data parsing suitable for further analysis or manipulation.

The article explains how to use the `compgen -v` command in Bash to list shell variables and filter them with regex patterns using `grep`. Examples demonstrate how to find variables starting with 'USER', containing 'path', or ending with '_id'. It includes a Bash script to display variables containing 'USER', enhancing debugging and management of environment variables in scripting tasks.

Precompiling regex patterns in `awk` and `sed` enhances script efficiency when processing text in Linux. `awk` allows regex to be defined once, reducing reevaluation, while `sed`, lacking native precompilation, uses shell variables for similar gains. This approach improves both performance and script maintainability.

This article explores using `grep` with lookarounds in Linux to detect overlapping text patterns. It discusses the `-o` option for outputting exact matches and the requirement of the `-P` option for Perl-compatible regular expressions. Examples include matching email domains and specific string parts, addressing installation and support for these features across different Linux distributions.