#!/bin/sh# tx9 installer -- served by https://tx9.davis7.sh/install (decision 10,# docs/tx9-cli-design.md).##   curl -fsSL https://tx9.davis7.sh/install | sh## Detects OS/arch, downloads the matching tx9 release binary + its# checksums.txt from the latest GitHub release, verifies the checksum, and# installs to ~/.local/bin/tx9 (override with TX9_INSTALL_DIR).## Asset naming is the one invariant this script shares with# internal/selfupdate.AssetName, the Makefile's `dist` target, and# .github/workflows/release.yml: plain, uncompressed executables named# tx9_<os>_<arch>, verified against a checksums.txt release asset in# `sha256sum` output format ("<64-hex-digest>  <filename>" per line).## Deliberately plain POSIX sh + curl: no jq, no GitHub API call -- the# stable /releases/latest/download/<asset> URL shape resolves straight to# the current release's asset without needing to parse JSON.set -eu REPO="davis7dotsh/tx9"INSTALL_DIR="${TX9_INSTALL_DIR:-$HOME/.local/bin}" log() {  printf 'tx9-install: %s\n' "$*" >&2} die() {  log "$*"  exit 1} need() {  command -v "$1" >/dev/null 2>&1 || die "'$1' is required to install tx9"} detect_os() {  case "$(uname -s)" in    Linux) echo linux ;;    Darwin) echo darwin ;;    *) die "unsupported OS: $(uname -s) (tx9 currently ships Linux and macOS binaries)" ;;  esac} detect_arch() {  case "$(uname -m)" in    x86_64 | amd64) echo amd64 ;;    aarch64 | arm64) echo arm64 ;;    *) die "unsupported architecture: $(uname -m) (tx9 currently ships amd64 and arm64 binaries)" ;;  esac} need curlneed unameneed mktempneed mkdirneed chmodneed mvneed awk os=$(detect_os)arch=$(detect_arch)asset="tx9_${os}_${arch}" base_url="https://github.com/${REPO}/releases/latest/download"asset_url="${base_url}/${asset}"checksums_url="${base_url}/checksums.txt" tmpdir=$(mktemp -d)trap 'rm -rf "$tmpdir"' EXIT INT TERM HUP log "downloading ${asset}..."if ! curl -fsSL "$asset_url" -o "$tmpdir/$asset"; then  die "download failed: $asset_url (no release published yet, or an unsupported platform)"fi log "downloading checksums.txt..."if ! curl -fsSL "$checksums_url" -o "$tmpdir/checksums.txt"; then  die "download failed: $checksums_url"fi expected=$(awk -v want="$asset" '$2 == want { print $1; found=1 } END { if (!found) exit 1 }' "$tmpdir/checksums.txt") \  || die "no checksum entry for ${asset} in checksums.txt" if command -v sha256sum >/dev/null 2>&1; then  actual=$(sha256sum "$tmpdir/$asset" | awk '{ print $1 }')elif command -v shasum >/dev/null 2>&1; then  actual=$(shasum -a 256 "$tmpdir/$asset" | awk '{ print $1 }')else  die "neither sha256sum nor shasum found; cannot verify ${asset} (install them, or download and verify manually)"fi [ "$actual" = "$expected" ] || die "checksum mismatch for ${asset}: got ${actual}, want ${expected} (not installing)" mkdir -p "$INSTALL_DIR"chmod 0755 "$tmpdir/$asset"mv "$tmpdir/$asset" "$INSTALL_DIR/tx9" log "installed tx9 to ${INSTALL_DIR}/tx9" case ":${PATH}:" in  *":${INSTALL_DIR}:"*) ;;  *)    log "note: ${INSTALL_DIR} is not on your PATH. Add it to your shell profile, e.g.:"    log "  export PATH=\"${INSTALL_DIR}:\$PATH\""    ;;esac if version=$("$INSTALL_DIR/tx9" version 2>/dev/null); then  log "tx9 ${version} ready"else  log "installed, but 'tx9 version' did not run cleanly -- check ${INSTALL_DIR}/tx9 manually"fi