macbash

Check and fix bash scripts so they work on macOS.
Detects GNU/Linux-specific bash constructs that won't work on macOS. Can auto-fix many issues.

Install

# Quick install
curl -fsSL https://raw.githubusercontent.com/hypersec-io/macbash/main/packaging/install.sh | sh

# Homebrew
brew tap hypersec-io/tools && brew install macbash

# Debian/Ubuntu
curl -LO https://github.com/hypersec-io/macbash/releases/latest/download/macbash_1.0.0_amd64.deb
sudo dpkg -i macbash_1.0.0_amd64.deb

# RHEL/Fedora
curl -LO https://github.com/hypersec-io/macbash/releases/latest/download/macbash-1.0.0-1.x86_64.rpm
sudo rpm -i macbash-1.0.0-1.x86_64.rpm

# From source
go install github.com/hypersec-io/macbash/cmd/macbash@latest

Usage

macbash script.sh                        # Check for issues
macbash -w script.sh                     # Fix and overwrite in-place
macbash -o fixed.sh script.sh            # Fix to new file
macbash --format json scripts/*.sh       # JSON output for CI
macbash --config custom-rules.yaml *.sh  # Custom rules

Exit codes: 0 = clean, 1 = errors, 2 = warnings only

What It Catches

GNU Coreutils (Error)

Issue	Problem	Fix
sed -i	BSD requires backup extension	sed -i '' or sed -i.bak
grep -P	Perl regex is GNU-only	grep -E (auto-converts simple patterns)
readlink -f	GNU-only	cd/pwd -P combo
date -d	GNU-only date parsing	date -j -f on BSD
stat -c	GNU format option	stat -f on BSD
xargs -r	GNU no-run-if-empty	Remove (BSD default)
find -printf	GNU-only	-exec stat
sort -V	GNU version sort	Custom function
timeout	GNU coreutils	gtimeout via Homebrew

Bash 4+ Features (Error)

macOS ships bash 3.2 (GPLv3 licensing):

Feature	Version	Alternative
declare -A	4.0+	Indexed arrays
${var,,} ${var^^}	4.0+	tr
mapfile/readarray	4.0+	while-read loop
|&	4.0+	2>&1 |
${arr[-1]}	4.3+	${arr[${#arr[@]}-1]}

Portability (Warning/Info)

Issue	Severity	Fix
echo -e	Warning	printf "%b"
echo -n	Info	printf "%s"
#!/bin/bash	Info	#!/usr/bin/env bash
gawk	Warning	awk

Custom Rules

version: "1.0"
rules:
  - id: my-rule
    name: "Custom check"
    description: "What this catches"
    severity: warning
    pattern: 'some\s+pattern'
    negative_pattern: 'exclude\s+this'
    fix_type: suggest
    fix_template: "Use this instead"
    tags: [custom]

CI Integration

- name: Check bash portability
  run: |
    go install github.com/hypersec-io/macbash/cmd/macbash@latest
    macbash scripts/*.sh

JSON output for reporting:

{
  "total_issues": 2,
  "errors": 1,
  "warnings": 1,
  "matches": [
    {
      "file": "script.sh",
      "line": 5,
      "rule_id": "grep-perl-regex",
      "severity": "error",
      "content": "grep -P '\\d+' file.txt",
      "fix": "grep -E or perl -ne"
    }
  ]
}

Development

go build ./cmd/macbash
go test ./...
golangci-lint run

License

Apache-2.0