Zig master branch build version updater bash script.

zig-up

#!/bin/bash
set -Eeuo pipefail
trap cleanup SIGINT SIGTERM ERR EXIT

# Zig Update; Check and download the latest zig master branch build
# Inspired by: https://gist.github.com/MasterQ32/1f27081d8a7dd109fc290bd6729d97a8

ROOT_DIR=/usr/local/bin
TMP_DIR=/tmp/zig-up
REPO_URL=https://ziglang.org/download/index.json
REPO_ARCH=x86_64-linux

cleanup() {
  trap - SIGINT SIGTERM ERR EXIT
  rm -r "${TMP_DIR}"
}

msg() { echo >&2 -e "${1-}"; }
die() { msg "$@"; exit 1; }

mkdir -p "${TMP_DIR}"

test -d "${ROOT_DIR}" || die "Root directory \"${ROOT_DIR}\" does not exist!"
type curl >/dev/null 2>&1 || die "curl is required but not available!"
type jq >/dev/null 2>&1 || die "jq is required but not available!"
type shasum >/dev/null 2>&1 || die "shasum is required but not available!"

msg "Getting version info..."

repo=$(curl -s "${REPO_URL}" | jq ".master[\"${REPO_ARCH}\"]") || die "Failed to aquire version info!"
tarball=$(echo "${repo}" | jq --raw-output '.tarball')
shasum=$(echo "${repo}" | jq --raw-output '.shasum')
size=$(echo "${repo}" | jq --raw-output '.size')
filename=${tarball##*/} # basename
version=${filename%.tar.xz}

test "${tarball:0:27}" == "https://ziglang.org/builds/" || die "Unexpected download path!"
test -z "${version}" && die "Failed to extract version info!"

if test "${ROOT_DIR}/zig-latest/zig" -ef "${ROOT_DIR}/${version}/zig"; then
  msg "${version} is already the current version!"
else
  msg "Updating to ${version}"

  curl "${tarball}" -o "${TMP_DIR}/${filename}" || die "Failed to download!"
  echo "${shasum}  ${TMP_DIR}/${filename}" | shasum -c - || die "Failed to verify checksum!"
  test "${size}" -eq "$(stat -c '%s' "${TMP_DIR}/${filename}")" || die "Download size mismatch!"

  tar -xJC "${ROOT_DIR}" -f "${TMP_DIR}/${filename}" || die "Failed to extract!"
  rm -rf "${ROOT_DIR}/zig-latest" "${ROOT_DIR}/zig_" || die "Failed to remove old symlinks!"
  ln -s "${version}" "${ROOT_DIR}/zig-latest" || die "Failed to set new symlink!"
  ln -s zig-latest/zig "${ROOT_DIR}/zig_" || die "Failed to set new symlink!"

  # Clean up old versions; keep the last 5 downloads
  find "${ROOT_DIR}"/zig-linux-x86_64-* -prune | head -n -5 | while IFS='' read -r path; do
    rm -r "$path"
  done
fi

msg "Current version: $("${ROOT_DIR}/zig-latest/zig" version)"