#!/usr/bin/env bash

format="%H:%M"
current_time=$(date +"$format")
time="${1:-$current_time}"

C_RESET=`tput sgr0`
C_GRAY="$(tput setaf 7)$(tput dim)";
C_HIGHLIGHT="$(tput setaf 7)$(tput bold)"

label() { printf "$C_GRAY$1: $C_HIGHLIGHT"; }
space() { echo -e "$C_RESET"; }

space

label "IST -> CET"
TZ=CET date --date="$time IST" +"$format CET"

space

label "CET -> IST"
date --date="$time CET" +"$format IST"

space