Script to check if drives are spun down (idle)

check_drives.sh

#!/usr/bin/env bash
##
## Title:                     check_drives.sh
## Description:               Script to check if drives are spun down (idle)
## Author:                    B. van wetten
## Created date:              11-02-2020
## Updated date:              17-02-2020
## Version:                   0.1.3
## GitHub Gist:               https://gist.github.com/QNimbus/cd4432ed283d1f97d3cf9065923e566b
##
## Usage:                     check_drives.sh
##
## Reference:                 https://en.wikipedia.org/wiki/S.M.A.R.T.#Known_ATA_S.M.A.R.T._attributes

# Shell utilities
GETOPT=$(which getopt); [[ $? != 0 ]] && echo "Command 'getopt' not found" >&2 && exit 1
SMARTCTL=$(which smartctl); [[ $? != 0 ]] && echo "Command 'smartctl' not found" >&2 && exit 1

# Initialize variables
_ME=$(basename "${0}")
_LOG=check_drives.log
_DEVS=($(smartctl --scan --nocheck standby -d scsi | awk '{print $1}'))
_IGNORE_DEVS=()

# Option strings
SHORT=hm:i:
LONG=help,minutes:,ignore:

#Send stderr & stdout to logfile
exec > >(tee -i $_LOG) 2>&1

# Get command line arguments
if [[ "${#}" -gt 0 ]]
then
  getopt -T > /dev/null
  if [ $? -eq 4 ]; then
    # GNU enhanced getopt is available
    _ARGS=$(${GETOPT} --name "$_ME" --long ${LONG} --options ${SHORT} -- "$@")
  else
    # Original getopt is available (no long option names, no whitespace, no sorting)
    _ARGS=$(${GETOPT} ${SHORT} "$@")
  fi
  if [ $? -ne 0 ]; then
    echo "$_ME: usage error (use -h for help)" >&2
    exit 2
  fi
fi

###############################################################################
# Functions                                                                   #
###############################################################################

# _print_usage()
#
# Usage:
#   _print_usage
#
# Print the program usage information.
_print_usage() {
   cat <<HEREDOC
____ _  _ ____ ____ _  _     ___  ____ _ _  _ ____ ____ 
|    |__| |___ |    |_/      |  \ |__/ | |  | |___ [__  
|___ |  | |___ |___ | \_ ___ |__/ |  \ |  \/  |___ ___]

Usage:
  ${_ME} -m 60 -i /dev/da0 /dev/da1
  ${_ME} -h

Options:
  -i        Ignore certain devices
  -m        Run check every x minutes
  -h        Show this screen

HEREDOC
   exit ${1:-0}
}

# _parse_commandline_arguments()
#
# Usage:
#   _parse_commandline_arguments
#
# Parses and validates commandline arguments and populates appropriate variables.
_parse_commandline_arguments()
{
   while true;
   do
      case "${1:-}" in
          -i|--ignore)
            while
              if ! [[ -z "${2}" || "${2}" =~ ^-{1,2} ]]
              then
                _IGNORE_DEVS+=("${2}")
                shift 1
              fi
              ! [[ -z "${2}" || "${2}" =~ ^-{1,2} ]]
            do
              :
            done
            shift 1
            ;;
          -m|--minutes)
            [[ -z "${2}" || "${2}" == *[[:space:]]* || "${2}" == -* ]] && { echo "$_ME: $1 needs a value" >&2; _print_usage 1; }
            _set_variable _INTERVAL $(("${2}"*60))
            shift 2
            ;;
          \?) echo "$_ME: Unknown option -$1" >&2;
            exit 1
            ;;
          :) echo "$_ME: -$1 needs a value" >&2;
            exit 1 
            ;;
          *) shift
            break
            ;;
      esac
   done
}

# _validate_parameters()
#
# Usage:
#   _validate_parameters
#
# Performs several checks on the supplied command line arguments
_validate_parameters() {
  :
}

# _set_variable()
#
# Usage:
#   _set_variable variable value
#
# Sets the variable to a value if not already set. Otherwise exits with an error message
_set_variable()
{
   local varname="$1"
   shift
   if [ -z "${!varname:-}" ]; then
      eval "$varname=\"$@\""
   else
      echo "Error: $varname already set"
      usage
   fi
}

# _print_header()
#
# Usage:
#   _print_header
#
# Prints a header to the output
_print_header() {
   _DATE=$(date +"%A, %b %d %Y")
   printf "########################################################## %*s ###\n" 22 "${_DATE}"
   printf "%-10s %12s %20s %35s %4s\n" "Time" "Device" "Model" "State" "Temp"
   printf "=%.0s" {1..85}
   printf "%b" "\n"
}

# _print_separator()
#
# Usage:
#   _print_separator
#
# Prints a line separator to the output
_print_separator() {
   printf -- "-%.0s" {1..85}
   printf "%b" "\n"
}

###############################################################################
# Main                                                                        #
###############################################################################

# _main()
#
# Usage:
#   _main [<options>] [<arguments>]
#
# Description:
#   Entry point for the program, handling basic option parsing and dispatching.
_main() {
  # Avoid complex option parsing when only one program option is expected.
  if [[ "${@:-}" =~ -h|--help ]]
  then
    _print_usage
  else
    _parse_commandline_arguments "$@"

    _validate_parameters

    # Initialize throwaway array
    tmp=()
    for DEV in "${_DEVS[@]}"
    do
        skip=
        for IGNORE_DEV in "${_IGNORE_DEVS[@]}"
        do
            [[ "$DEV" == "$IGNORE_DEV" ]] && { skip=1; break; }
        done
        [[ -n $skip ]] || tmp+=("$DEV")
    done

    # Copy array
    _DEVS=("${tmp[@]}")

    # Remove throwaway array
    unset tmp

    # Output header
    _print_header

    # Run once or on interval
    while
      # All drives idle
      idle=0
      for DEV in "${_DEVS[@]}"
      do
        _SMART_OUTPUT=$(${SMARTCTL} --nocheck standby --all "${DEV}")
        _RETURN=$?

        # Get S.M.A.R.T. data and attributes
        _TEMPERTATURE=$(echo "${_SMART_OUTPUT}" | grep "Temperature_Celsius" | grep -o "..$")
        _DEVICE_MODEL=$(echo "${_SMART_OUTPUT}" | grep "Device Model" | awk {'print $NF'})

        # Check bit 0 - See https://linux.die.net/man/8/smartctl 'Return values'
        if [[ $_RETURN -eq 0 ]]
        then
          _STATE="SPINNING"
        # Check bit 1 - See https://linux.die.net/man/8/smartctl 'Return values'
        elif [[ $(( $_RETURN & 2**1 )) -ne 0 ]]
        then
          _STATE="STANDBY"
        # Check bit 2 - See https://linux.die.net/man/8/smartctl 'Return values'
        elif [[ $(( $_RETURN & 2**2 )) -ne 0 ]]
        then
          _STATE="S.M.A.R.T. ERROR or UNSUPPORTED"
        # Check bit 3 - See https://linux.die.net/man/8/smartctl 'Return values'
        elif [[ $(( $_RETURN & 2**3 )) -ne 0 ]]
        then
          _STATE="DISK FAILING"
        else
          _STATE="UNKNOWN ERROR"
        fi
        _TIME=$(date "+%H:%M:%S")
        printf "%-10s %12s %20s %35s %4s\n" "${_TIME}" "${DEV}" "${_DEVICE_MODEL:-UNKNOWN}" "${_STATE:-UNKNOWN}" "${_TEMPERTATURE:--}"
      done
      
      # Output separator
      _print_separator

      # This is to emulate a 'do-while' construct in Bash
      # If the statement below evaluates to 'true' the loop will continue
      [[ ! -z $_INTERVAL ]] && sleep $(("${_INTERVAL}"))
    do
      :
    done
  fi
}

# Call `_main` after everything has been defined.
_main "$@"

exit ${exitcode:-0}