How to convert UTC to local time in a shell script on linux

Question

I have a string of the format

20110724T080000Z

and I want to convert that to local time in a shell script on linux. I thought I simply could give it as input to date, but I don't seem to be able to tell date what format my input date has.

this

date -d "20110724T080000Z" -u

would make date complain

date: invalid date `20110724T080000Z'

Also, what is the format of the form "20110724T080000Z" called? I have had little success trying to google for it.

Answer 1

That's ISO8601 "basic format" for a combined date and time. date does not seem to be able to parse 20110724T080000Z, but if you are prepared to do a few string substitutions it parses 20110724 08:00:00Z correctly.

Answer 2

The date program recognizes yyyy-mm-ddTHH:MM:SS (as well as yyyy-mm-dd HH:MM:SS), so:

a=20110724T080000Z
b=${a:0:4}-${a:4:2}-${a:6:5}:${a:11:2}:${a:13:2}
date +%F_%T -d "${b} +0"

Would print 2011-07-24_12:30:00 in my locale.