date +%Z

-05:00 EST

$ cat /etc/timezone

Asia/Kolkata

$ strings /etc/localtime | tail -n 1
MST7MDT,M3.2.0,M11.1.0

# timedatectl
      Local time: Tue 2016-09-13 17:10:26 EDT
  Universal time: Tue 2016-09-13 21:10:26 UTC
        RTC time: Tue 2016-09-13 21:10:26
       Time zone: US/Eastern (EDT, -0400)
 Network time on: yes
NTP synchronized: yes
 RTC in local TZ: no

# timedatectl status | grep "zone" | sed -e 's/^[ ]*Time zone: (.*) (.*)$/1/g'`
US/Eastern