NT epoch to Linux epoch converter

w32tm.sh

#!/bin/bash
#
# Most versions of Unix, for example, use January 1, 1970 (1970-01-01 00:00:00) as the epoch date
# Windows uses January 1, 1601 (1601-01-01 00:00:00)
# Macintosh systems use January 1, 1904 (1904-01-01 00:00:00)
# Digital Equipment Corporation's Virtual Memory System (VMS) uses November 17, 1858 (1858-11-17 00:00:00)

offset=$((134774*24*60*60))     # number of days from Jan 1st 1601 to Jan 1st 1970 (incl leap year days), converted to seconds
timestamp=$1                    # windows timestamp
format=$2

human () {
 date -d @${unixTimestamp} '+%F %T %Z'                            # display that timestamp in YYYY-MM-DD HH:MM:SS TZ
 (TZ=":Europe/Stockholm" date -d @${unixTimestamp} '+%F %T %Z')   # display that timestamp in YYYY-MM-DD HH:MM:SS TZ with localized time zone
}

epoc () {
 unixTimestamp=$((timestamp/10000000-offset))           # convert 100-nanosecond interval to second, adjust for offset
 if [ "${format}" == "human" ]; then
    human
 else
    echo linux epoc: ${unixTimestamp}
 fi
}

if [ ! "${timestamp}" ]; then
    echo -e "\n \e[91mWindows epoc time missing\n\e[m"
    exit
fi

epoc