What are the various parts of the Kernel version number?

There are three parts to the version number:
Major number 2.4.18: represents very significant changes
Minor number 2.4.18: Release, even numbers are production and odd numbers are development
Micro number/Patch level 2.4.18: bug fixes and updates.

Some references designate the third number as the micro number and add a -<patch level> to the version number, e.g. 2.4.18-411.e15.

Note: Version numbers of distributions are independent of kernel version numbers
e.g. I have Red Hat 5.11 and here is version 2.6.18-411.el5

2      .     6       .    18       -          411.el5

|            |            |                    | --> patch level

|            |            | --> Micro Number

|            |

|            |--> Minor Number

|

|--> Major Number

Find kernel versions

You can pull the kernel version using different commands.

$ uname –r

2.6.18-411.el5

$

$ uname –a

$ cat /proc/version

Linux version 2.6.18-411.el5 (mockbuild@x86-001.build.bos.redhat.com) (gcc version 4.1.2 20080704 (Red Hat 4.1.2-55)) #1 SMP Thu Jun 2 02:56:21 EDT 2015

$

$ ls –l /boot

$ dmesg | grep Linux