apps installer

Installer

Active contributors: Nik Anand

What it does

install.sh is a 142-line POSIX shell script. It detects the host OS and architecture, downloads the matching skill-registry tarball from the latest GitHub Release, extracts the binary, and drops it into ~/.local/bin/skill-registry. The user invokes it through curl … | sh and never sees Python during onboarding — the Python MCP server is installed later by the Go wizard.

curl -fsSL https://raw.githubusercontent.com/anand-92/skills-registry/main/install.sh | sh

Why POSIX sh and not Bash

The script must run unmodified on macOS (where /bin/sh is still BSD-flavored), Debian/Ubuntu, Alpine (ash), and inside CI containers that may lack bash. Every construct is plain sh: case for OS/arch dispatch, no arrays, no [[ … ]]. set -eu is enabled so a missing variable or any failed command aborts immediately.

OS and arch detection

detect_os() and detect_arch() shell out to uname -s and uname -m, normalize the result, and exit 2 for anything they can't match. The supported matrix:

uname -s	Normalized OS
Linux, linux	linux
Darwin, darwin	darwin

uname -m	Normalized arch
x86_64, amd64	amd64
arm64, aarch64	arm64

Anything else prints a clear "unsupported" message to stderr and exits 2. The script never silently downloads the wrong asset.

Download path

build_url() produces the canonical Release asset URL:

• latest → https://github.com/<repo>/releases/latest/download/skill-registry_<os>_<arch>.tar.gz
• pinned vX.Y.Z → https://github.com/<repo>/releases/download/<version>/skill-registry_<os>_<arch>.tar.gz

download_to() tries curl -fsSL --retry 3 first, then wget -q -O if curl isn't on PATH. If neither is available, the script exits 1 with a clear "need curl or wget" message.

Extraction and placement

The script creates a tempdir with mktemp -d (fallback to mktemp -d -t skill-registry-install on older BSDs), traps EXIT INT TERM so the dir is removed even on Ctrl-C, then extracts only the skill-registry entry from the tarball:

tar -xzf "$tarball" -C "$tmpdir" "$BINARY"

The binary is moved into $BIN_DIR (default ~/.local/bin), then chmod +x is applied. If $BIN_DIR is not on $PATH the script prints a warning suggesting the user add it to their shell rc — it does not silently mutate the user's profile.

Environment variables

Every behavior is overridable so the script can be exercised end-to-end without hitting GitHub.

Variable	Default	Effect
SKILLS_REGISTRY_REPO	anand-92/skills-registry	Owner/repo to pull releases from.
SKILLS_REGISTRY_VERSION	latest	Pin to a specific release tag (e.g. v0.5.1).
SKILLS_BIN_DIR	$HOME/.local/bin	Install directory.
SKILLS_REGISTRY_OS	$(uname -s)	Override OS detection (useful for testing).
SKILLS_REGISTRY_ARCH	$(uname -m)	Override arch detection.
SKILLS_REGISTRY_URL	derived	Override the full tarball URL.
SKILLS_REGISTRY_TARBALL	unset	Use a local tarball path instead of downloading.
SKILLS_REGISTRY_DRY_RUN	unset	Print the resolved URL/dest and exit 0 without downloading.

The dry-run knob is used in the release smoke tests: piping through SKILLS_REGISTRY_DRY_RUN=1 lets CI verify the URL the script would hit without actually pulling bytes.

Exit codes

Code	Meaning
0	Success.
1	Generic / IO failure (download failed, binary not in archive, no curl or wget).
2	Unsupported OS or architecture.

Key source files

File	Role
install.sh	The whole installer. POSIX sh, 142 LOC.

Cross-references

• overview/architecture — how the installer fits into the three-deliverable picture.
• overview/getting-started — what to do after install.sh finishes.
• apps/cli/wizard-and-hub — the wizard that runs on first invocation of skill-registry.