Figure out the days where daylight savings will change

dst

# Function to figure out daylight savings dates for the current year
dst() {
  local TZ
  # RHEL7 / systemd
  if command -v timedatectl >/dev/null 2>&1; then
    TZ=$(timedatectl status | awk -F ': ' '/Time zone/{print $2}' | awk '{print $1}')
  # RHEL5, RHEL6 and similar aged CentOS/Fedora/etc
  elif [[ -r /etc/sysconfig/clock ]]; then
    TZ=$(awk -F "=" '/ZONE/{print $2}' /etc/sysconfig/clock)
  # Older Debian family
  elif [[ -r /etc/timezone ]]; then
    TZ=$(</etc/timezone)
  # Solaris 11
  elif command -v nlsadm >/dev/null 2>&1; then
    TZ=$(nlsadm get-timezone | cut -d '=' -f2)
  # Older Solaris
  elif [[ -r /etc/TIMEZONE ]]; then
    TZ=$(nawk -F '=' '/TZ=/{print $2}' /etc/TIMEZONE)
  fi

  zdump -v "${TZ:-NZ}" \
    | grep "$(date '+%Y').*isdst=1" \
    | tail -n 2 \
    | awk '{print $4, $3, $6}'
}