I need to convert a unix timestamp (number of seconds since 2000) into a standard human-readable format. I found that the command
date -d @392603388.257982 works like a charm but the default start date is 1970.
A linux timestamp (wiki) is counted since 1st January 1970. Where did the year 2000 come from? Is it a homework? If yes, then you could use
date but simply increase given timestamp (counted from 2000) by number of seconds that passed until year 2000 (I got it with following command:
date -u +"%s" -d "1/1/2000").
Och, and look out for time zone, that's why I've added
-u switch above.
If your timestamp number is in seconds, you could just add it to
2000-01-01T00:00:00. With GNU date that's as simple as
date -d "2001-01-01Z +$n seconds"
I've included a
Z there to indicate that your epoch is specified in Zulu (UTC) time - if your epoch is actually in local time, you should omit that.