Script for calculating time left for current Cardano epoch

calculate.sh

#!/bin/bash

getEpoch(){
 CCLI=$(which cardano-cli)
 "$CCLI" query tip --mainnet | sed -n '3 p'| sed 's/[^0-9]*//g'
}

# Description : Calculation of days, hours, minutes and seconds from time in seconds
timeLeft() {
  local T=$1
  local D=$((T/60/60/24))
  local H=$((T/60/60%24))
  local M=$((T/60%60))
  local S=$((T%60))
  (( D > 0 )) && printf '%dd ' $D
  printf '%02d:%02d:%02d' $H $M $S
}

calculateTimeLeft() {

###################
# Preview Network #
###################
#SHELLEY_TRANS_EPOCH=0;
#BYRON_SLOT_LENGTH=20000;
#BYRON_EPOCH_LENGTH=4320;
#SLOT_LENGTH=1;
#EPOCH_LENGTH=86400;
#BYRON_GENESIS_START_SEC=1666656000;

###########
# Mainnet #
###########

  SHELLEY_TRANS_EPOCH=208
  BYRON_SLOT_LENGTH=20000
  BYRON_EPOCH_LENGTH=21600
  SLOT_LENGTH=1
  EPOCH_LENGTH=432000
  BYRON_GENESIS_START_SEC=1506203091

  current_time_sec=$(printf '%(%s)T\n' -1)

  echo $(( ((SHELLEY_TRANS_EPOCH * BYRON_SLOT_LENGTH * BYRON_EPOCH_LENGTH) / 1000) + (($(getEpoch) + 1 - SHELLEY_TRANS_EPOCH) * SLOT_LENGTH * EPOCH_LENGTH) - current_time_sec + BYRON_GENESIS_START_SEC ))
}

formattedTimeLeft=$(timeLeft $(calculateTimeLeft))
echo $formattedTimeLeft