shell-portability

Write shell scripts using POSIX-compliant syntax and features supported by both bash and sh. Avoid bash-specific extensions, use portable command alternatives across platforms, detect the environment at runtime, and test on target systems to ensure cross-platform compatibility.

POSIX sh is a minimal standard shell; bash extends it with additional features. Handle both by writing to POSIX standards, using feature detection, providing fallback implementations for bash-only features, and selecting appropriate shebangs for your script's requirements.

Ensure portability by using POSIX-compliant commands, avoiding platform-specific tools, handling command variations with conditional logic, detecting the OS and shell at runtime, following ShellCheck guidance, and providing documented workarounds for known platform quirks.

Use `#!/bin/sh` for maximum POSIX compatibility across systems, or `#!/usr/bin/env sh` for environments where sh may not be in /bin. Avoid bash-specific shebangs unless your script requires bash features unavailable in POSIX sh.

Scripts fail across systems due to non-POSIX features, platform-specific command variations, shell dialect differences, and missing environment setup. Diagnose with ShellCheck, verify POSIX compliance, test command availability on target platforms, and implement portable fallbacks.

Yes, by writing strictly portable scripts using POSIX syntax, avoiding platform-specific commands, handling path separators and line endings correctly, and detecting the runtime environment. Test on all target platforms and provide fallback implementations for OS-specific operations.