Regex for Log Files: Extract Fields from Apache and Nginx
Parse structured and semi-structured log files with regex. Extract timestamps, IPs, status codes, and messages from Apache, Nginx, and JSON logs.
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Tags: developer-tools, regex, logging
Regex for Log Files: Extract Fields From Apache, Nginx, and App Logs Log parsing is one of the highest-value regex use cases. Logs are structured text that humans write in ad hoc formats — and regex is exactly the right tool for extracting fields from structured text. This article covers working patterns for Apache, Nginx, JSON logs, timestamps, and custom application logs, plus grep/ripgrep command examples you can run immediately. --- Apache Combined Log Format Apache's Combined Log Format is the default for most Apache installations and is also used by many other servers: Fields in order: IP, ident, auth user, timestamp, request, status code, bytes, referer, user agent. Full Combined Log Pattern Named capture groups (PCRE/Python): Captures from the example line: IP: Ident: Auth user:…
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