This presentation provides a deep dive into advanced Bash scripting techniques. It covers crucial topics like regular expressions for pattern matching, utilizing built-in commands for string manipulation and file processing, and leveraging external utilities like sed and awk for more complex operations. The guide emphasizes practical scripting skills, demonstrating how to control program flow with loops and conditional statements, handle signals and traps for robust script behavior, and effectively manage variables and functions for modular and reusable code. It also delves into input/output redirection, process management, and here documents, equipping users to write powerful and efficient shell scripts for automating various system administration tasks.
Koto is a modern, general-purpose programming language designed for ease of use and performance. It features a dynamically typed system with optional type hints, garbage collection, and built-in support for concurrency through asynchronous functions and channels. Koto emphasizes functional programming paradigms but also allows for imperative and object-oriented styles. Its syntax is concise and readable, drawing inspiration from languages like Python and Lua. Koto aims to be embeddable, with a small runtime and the ability to compile to bytecode or native machine code. It is actively developed and open-source, promoting community involvement and contributions.
Hacker News users discussed Koto's design choices, praising its speed, built-in concurrency support based on fibers, and error handling through optional values. Some compared it favorably to Lua, highlighting Koto's more modern approach. The creator of Koto engaged with commenters, clarifying details about the language's garbage collection, string interning, and future development plans, including potential WebAssembly support. Concerns were raised about its small community size and the practicality of using a niche language, while others expressed excitement about its potential as a scripting language or for game development. The discussion also touched on Koto's syntax and its borrow checker, with commenters offering suggestions and feedback.
Rhai is a fast and lightweight scripting language specifically designed for embedding within Rust applications. It boasts a simple, easy-to-learn syntax inspired by JavaScript and Rust, making it accessible for both developers and end-users. Rhai prioritizes performance and safety, leveraging Rust's ownership and borrowing system to prevent data races and other memory-related issues. It offers seamless integration with Rust, allowing direct access to Rust functions and data structures, and supports dynamic typing, custom functions, modules, and even asynchronous operations. Its versatility makes it suitable for a wide range of use cases, from game scripting and configuration to data processing and rapid prototyping.
HN commenters generally praised Rhai for its speed, ease of embedding, and Rust integration. Several users compared it favorably to Lua, citing better performance and a more "Rusty" feel. Some appreciated its dynamic typing and scripting-oriented nature, while others suggested potential improvements like static typing or a WASM target. The discussion touched on use cases like game scripting, configuration, and embedded systems, highlighting Rhai's versatility. A few users expressed interest in contributing to the project. Concerns raised included the potential performance impact of dynamic typing and the relatively small community size compared to more established scripting languages.
Summary of Comments ( 57 )
https://news.ycombinator.com/item?id=43714594
HN commenters generally praise the linked Bash scripting guide for its clarity and comprehensiveness, especially regarding lesser-known features and best practices. Several highlight the sections on quoting and variable expansion as particularly valuable for avoiding common pitfalls. Some suggest the guide, while older, remains relevant for intermediate/advanced users looking to solidify their understanding. A few users mention alternative resources or offer minor critiques, such as the guide's lack of coverage on newer Bash features or the density of information, but the overall sentiment is positive, viewing the PDF as a valuable resource for improving Bash scripting skills. The mention of
set -u(nounset) to catch undefined variables is brought up multiple times as a crucial takeaway.The Hacker News post titled "Advanced Shell Scripting with Bash (2006) [pdf]" linking to a presentation by Mendel Cooper has several comments discussing the content and its relevance.
Many commenters praise the presentation for its clear explanations and coverage of important, often overlooked, Bash features. One user highlights the section on "eval" and its potential dangers, mentioning how the presentation effectively demonstrates safer alternatives. This commenter emphasizes the value of understanding these nuances for writing robust and secure scripts. Another user specifically points out the explanation of the difference between
localanddeclarewithin functions as particularly helpful, as it clarifies a common point of confusion.Several commenters discuss the enduring relevance of the material despite being from 2006. They argue that the core principles of shell scripting haven't changed significantly and that the presentation remains a valuable resource for both beginners and experienced scripters. One user points out that while newer shells like Zsh are gaining popularity, Bash remains prevalent, making the information in the presentation widely applicable. Another commenter echoes this sentiment, emphasizing the continued importance of Bash scripting for system administrators and developers.
Some users offer additional resources and tips related to Bash scripting. One user suggests using shellcheck, a static analysis tool, for catching potential errors and improving script quality. Another shares a link to the "Bash Pitfalls" page, which complements the presentation by further detailing common scripting mistakes.
The discussion also touches upon the broader context of shell scripting. One commenter expresses a preference for using more modern languages like Python for complex tasks, reserving shell scripts for simpler operations. However, another user counters this by highlighting scenarios where shell scripts remain highly effective, such as automating system administration tasks or quickly prototyping ideas.
In summary, the comments on the Hacker News post generally praise the linked presentation for its clear explanations of advanced Bash concepts. They acknowledge its continued relevance despite its age and emphasize the importance of understanding these concepts for writing effective and secure shell scripts. The discussion also includes helpful supplementary resources and touches upon the broader debate about the appropriate use cases for shell scripting in modern software development.