#!/usr/bin/env bash
# JoeC read-only Linux health snapshot. No state changes.
set -uo pipefail
printf 'UTC: %s\n' "$(date -u +'%FT%TZ')"
printf '\nOperating system:\n'
if [[ -r /etc/os-release ]]; then grep -E '^(PRETTY_NAME|VERSION_ID)=' /etc/os-release; fi
for tool in uptime free df; do
  if command -v "$tool" >/dev/null 2>&1; then
    printf '\n%s:\n' "$tool"
    case "$tool" in
      uptime) uptime || true ;;
      free) free -h || true ;;
      df) df -hT || true; df -i || true ;;
    esac
  fi
done
if command -v systemctl >/dev/null 2>&1; then
  printf '\nFailed systemd units:\n'
  systemctl --failed --no-pager || true
fi
printf '\nNo changes made. Redact hostnames, IPs and sensitive details before sharing.\n'