Find Exact Installation Date And Time Of Your Linux OS

On RHEL and its clones such as CentOS, Scientific Linux, Oracle Linux, you can find it using the following command:

rpm -qi basesystem

sample output is as below

Name : basesystem

Version : 10.0

Release : 7.el7.centos

Architecture: noarch

Install Date: Wed 16 Jul 2014 01:24:46 PM EEST

Group : System Environment/Base

Size : 0

License : Public Domain

Signature : RSA/SHA256, Fri 04 Jul 2014 03:46:57 AM EEST, Key ID 24c6a8a7f4a80 eb5

Source RPM : basesystem-10.0-7.el7.centos.src.rpm

Build Date : Fri 27 Jun 2014 01:37:10 PM EEST

Build Host : worker1.bsys.centos.org

Relocations : (not relocatable)

Packager : CentOS BuildSystem <http://bugs.centos.org>

Vendor : CentOS

Summary : The skeleton package which defines a simple CentOS Linux system

Description :

Basesystem defines the components of a basic CentOS Linux

system (for example, the package installation order to use during

bootstrapping). Basesystem should be in every installation of a system,

and it should never be removed.