TimeZone Converter

convert

#! /bin/bash -
#set -x
#
# Copyright (c) 2017 Joyent Inc.
#
# This script will convert times from one timezone to another.
# 
# Author: Jesse Butryn <jesse.butryn@joyent.com>
#
# 10/14/2017		- 	Initial draft.
#
##############################
# Table of Contents
##############################
#
# 1) Variables
# 2) Functions
# 3) Preflight
# 4) Run
#
##############################
# Section 1 Variables
##############################
CONVERT_LOCAL='US/Mountain'
TXT_BLD=$(tput bold)
TXT_YLW=$(tput setaf 3)
TXT_RED=$(tput setaf 1)
TXT_GRN=$(tput setaf 2)
TXT_WARN="${TXT_BLD}${TXT_YLW}"
TXT_ERR="${TXT_BLD}${TXT_RED}"
TXT_OKAY="${TXT_BLD}${TXT_GRN}"
TXT_RST=$(tput sgr0)
CONVERT_TZS=('UTC' 'MDT' 'PDT' 'CDT' 'EDT' 'BST' 'CEST' 'EEST' 'KST' 'SGT' 'AEST' 'NZDT')
##############################
# Section 2 Functions
##############################
echo.help () {

	cat <<EOF
	
This script will convert times from one timezone to another.

Usage: $(basename $0) '01/01/1970 10:00PM'
       $(basename $0) [MM/DD/YYYY HH:MM(AM/PM)] [HH:MM(AM/PM)]

EOF
	exit 10
	
}
chooseTZ () {

	PS3="${TXT_OKAY}Select a timezone: ${TXT_RST}"
	select CONVERT_TZ in "${CONVERT_TZS[@]}"; do
		case "$CONVERT_TZ" in
			UTC) echo 'UTC'; break ;;
			MDT) echo 'US/Mountain'; break ;;
			PDT) echo 'US/Pacific'; break ;;
			CDT) echo 'US/Central'; break ;;
			EDT) echo 'US/Eastern'; break ;;
			BST) echo 'Europe/London'; break ;;
			CEST) echo 'Europe/Berlin'; break ;;
			EEST) echo 'Europe/Vilnius'; break ;;
			KST) echo 'Asia/Seoul'; break ;;
			SGT) echo 'Asia/Singapore'; break ;;
			AEST) echo 'Australia/Sydney'; break ;;
			NZDT) echo 'Pacific/Auckland'; break ;;
		esac
	done
		
}
checkTIME () {

	CONVERT_CHK_TIME="$1"
	if [[ "$CONVERT_CHK_TIME" =~ ^(0[0-9]|1[0-2]):[0-9][0-9](AM|PM)$ ]]; then
		CONVERT_FORMAT='%I:%M%p'
	elif [[ "$CONVERT_CHK_TIME" =~ ^(0[0-9]|1[0-2])\/([0-2][0-9]|3[0-1])\/[0-9][0-9][0-9][0-9]\ (0[0-9]|1[0-2]):[0-9][0-9](AM|PM)$ ]]; then
		CONVERT_FORMAT='%m/%d/%Y %I:%M%p'
	else
		echo.help
		exit 1
	fi

}
##############################
# Section 3 Preflight
##############################
if [[ -n "$1" ]]; then
	checkTIME "$1"
	echo "Select an ${TXT_BLD}ORIGIN${TXT_RST} timezone"
	CONVERT_FROM="$(chooseTZ)"
	CONVERT_TIME="$(TZ="$CONVERT_FROM" date -j -f "$CONVERT_FORMAT" "$CONVERT_CHK_TIME" "+%s")"
else
	CONVERT_FROM="${CONVERT_LOCAL}"
	CONVERT_TIME="$(date "+%s")"
fi
echo "Select an ${TXT_BLD}DESTINATION${TXT_RST} timezone"
CONVERT_TO="$(chooseTZ)"
##############################
# Section 4 Run
##############################
TIME_IN="$(TZ="$CONVERT_FROM" date -j -f "%s" "$CONVERT_TIME")"
TIME_OUT="$(TZ="$CONVERT_TO" date -j -f "%s" "$CONVERT_TIME")"
cat <<EOF
${TXT_WARN}$TIME_IN${TXT_RST}
	Converts to:
${TXT_OKAY}$TIME_OUT${TXT_RST}
EOF