This repository tests different approaches for installing executable scripts using the install(1) command, with a focus on cross-platform portability between Linux (GNU coreutils) and macOS (BSD).

Latest test run: GitHub Actions Workflow

All required portability tests PASSED on both Linux and macOS.

When replacing a file owned by another user (e.g., root-owned in user-writable directory):

• install command: GNU coreutils 9.4
• Location: /usr/bin/install
• Kernel: Linux 6.11.0-1018-azure

• install command: BSD install
• Location: /usr/bin/install
• OS: macOS 15.7.2

Both of these patterns work reliably across Linux and macOS:

install -m 755 /dev/stdin target <<'EOF'
#!/usr/bin/env bash
echo "script content"
EOF

Pros:

• Works on both Linux and macOS
• Single command (atomic)
• Properly handles ownership changes on foreign-owned files
• Clean syntax for embedding scripts

Cons:

• None identified

tmp=$(mktemp)
printf '%s\n' "$SCRIPT_CONTENT" > "$tmp"
install -m 755 "$tmp" target
rm -f "$tmp"

Pros:

• Works on both Linux and macOS
• Properly handles ownership changes on foreign-owned files
• Good for content in variables
• Most traditional approach

Cons:

• Requires cleanup of temporary file
• Multiple commands (not atomic)

The pattern install -m 755 /dev/fd/0 target <<EOF also works on both platforms and is functionally equivalent to /dev/stdin.

The pattern echo "content" | install -m 755 /dev/stdin target has platform-dependent behavior:

• Linux (GNU coreutils): ✅ Works correctly
• macOS (BSD install): ❌ Fails with exit code 71

Do not use this pattern if cross-platform compatibility is needed.

The classic cat >file && chmod 755 file pattern has a critical flaw when the target file is owned by another user (e.g., root):

# If 'target' is owned by root but world-writable:
cat >target <<EOF  # ✅ Succeeds (file is writable)
#!/bin/bash
echo "new content"
EOF

chmod 755 target   # ❌ FAILS (you don't own the file)

This leaves the file with the new content but without execute permissions, breaking the script.

Both install approaches (heredoc and tempfile) solve this problem by atomically replacing the file, including ownership.

When replacing a file owned by another user (e.g., a root-owned file in a user-writable directory):

Both install methods properly handle ownership transfer, while cat + chmod breaks.

The test suite (test-install-portability.sh) validates:

1. Basic functionality of each approach
2. Proper handling of foreign-owned files (requires sudo)
3. Platform-specific behaviors

Run locally:

./test-install-portability.sh

1. For inline script content: Use install -m 755 /dev/stdin target <<EOF
2. For variable content: Use temporary file + install -m 755 "$tmp" target
3. Avoid: Piped stdin (echo | install /dev/stdin) for cross-platform code
4. Never use: cat >file && chmod when file ownership might change

• GNU coreutils install documentation
• FreeBSD install man page (similar to macOS BSD)
• Test workflow: .github/workflows/test-install-portability.yml