UnixTimestamp use

I have different file systems which store files as unix timestamp (date of data acquisition).
I would like to change files' time/name according to these unix timestamps.

It seems I can't use <UnixTimestamp> for this (pattern not found in Timestamp method).
Also UnixTimeStamp are in UTC and I want local time: would you advise me to do this in 2 steps (convert UnixTimestamp to readable dates then delta times)?

TiA

Mike

---