The following note will help you in finding the version of your Operationg system.


Linux
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#uname -a
Linux hostname 2.6.9-89.ELsmp #1 SMP Mon Apr 20 10:34:33 EDT 2009 i686 i686 i386 GNU/Linux

Example:---------------------
2.6.22-14-generic where,

2 : Kernel version
6 : The major revision of the kernel
22: The minor revision of the kernel
14: Immediate fixing / bug fixing for critical error
generic : Distribution specific string. For example, Redhat appends string such as EL5 to indicate RHEL 5 kernel.

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#lsb_release -a
LSB Version:    :core-3.0-ia32:core-3.0-noarch:graphics-3.0-ia32:graphics-3.0-noarch
Distributor ID: RedHatEnterpriseES
Description:    Red Hat Enterprise Linux ES release 4 (Nahant Update 8)
Release:        4
Codename:       NahantUpdate8

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#cat /etc/redhat-release
Red Hat Enterprise Linux ES release 4 (Nahant Update 8)

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#rpm -qa | grep release
redhat-release-4ES-9

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get Revision tree @ http://en.wikipedia.org/wiki/Red_Hat_Enterprise_Linux

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Solaris
-------
uname -a
cat /etc/release