How do I perform string replacement without Bash-specific syntax?

In a POSIX-compliant script, you should use standard utilities like 'sed' or 'tr' instead of the Bash-specific ${var//old/new} syntax.

What are common 'Bashisms' to avoid for POSIX compliance?

Common features to avoid include double brackets [[ ]], arrays, associative arrays, the function keyword, and specific string manipulations like ${var,,} for lowercase.

Can I use local variables in POSIX scripts?

While 'local' is technically a partial feature and not strictly POSIX, it is supported by most modern shells including dash, ash, and zsh, making it generally safe for use in most environments.

Why is #!/usr/bin/env bash preferred over #!/bin/bash?

Using /usr/bin/env bash searches the user's PATH to find the Bash executable, making the script more portable across different operating systems where Bash might be located in different directories.

Bash Portability & POSIX Compliance

Name: Bash Portability & POSIX Compliance
Author: Jamie-BitFlight

byJamie-BitFlight

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开发者工具

Ensures shell scripts run reliably across different environments by providing POSIX-compliant patterns and cross-shell compatibility guidance.

The Bash Portability skill is an essential resource for developers creating scripts that must function across various Unix-like systems, including macOS, Linux distributions using Dash as the default shell, and minimal container environments. It provides a structured comparison between standard POSIX features and Bash-specific extensions, offering ready-to-use patterns for string manipulation, conditionals, and array-like behavior that work regardless of the host shell. This skill helps eliminate 'it works on my machine' errors in CI/CD pipelines and deployment scripts by enforcing best practices for shebang selection and shell detection.

主要功能

01POSIX vs. Bash feature matrix for quick syntax validation.

02Shebang optimization for cross-system path resolution using /usr/bin/env.

0318 GitHub stars

04Guidance on using printf over echo for consistent output behavior.

05Portable alternatives for common Bashisms like double brackets and arrays.

06Detection logic for identifying shell types and versions at runtime.

使用场景

01Developing developer tools and installation scripts that must support Bash, Zsh, and Dash.

02Converting Bash-heavy scripts into minimal, POSIX-compliant sh scripts for Alpine Linux or BusyBox.

03Writing CI/CD pipeline scripts that need to run on diverse runner architectures.

What are Skills?·How to Install

Install with 🐟 Skill.Fish

npx skillfish add jamie-bitflight/claude_skills bash-portability

For use in Claude.ai and ChatGPT

Download Skill