miraheze-time.sh

#!/bin/bash

function print_24hr_string () {
  # Wrapper around "date" command for printing 24hr datetime
  # 1: "tzolson": timezone id from the Olson DB
  tzolson="$1"
  # 2: "placename": more relevant timezone label than Olson's choices
  placename="$2"
  # 3: "fdate" is "function date" for date passed to this func
  fdate="$3"
  isodate=$(TZ="$tzolson" date --date="${fdate}" -Im)  
  datefmt="* ${isodate}: %a %_d %B %Y %_I:%M%P %Z (${placename}; %-:::z UTC)"
  TZ="$tzolson" date --date="${fdate}" +"${datefmt}"
}


#MAIN

# "sdate" is "script date"
if [ -z "$1" ]; then
  # if $1 is not given on command line, use current UTC time
  sdate="$(date -u)"
else
  sdate="$1"
fi

print_24hr_string "Europe/Amsterdam" "Amsterdam" "${sdate}"
print_24hr_string "Europe/London" "London" "${sdate}"
print_24hr_string "UTC" "UTC" "${sdate}"
print_24hr_string "America/New_York" "New York" "${sdate}"
print_24hr_string "America/Los_Angeles" "Los Angeles" "${sdate}"