To find out the kernel version on a Red Hat Enterprise Linux 6 (RHEL 6) or CentOS 6 system, you can use the uname command. The uname command displays information about the system's kernel and other system information.
To display the kernel version, use the -r option:
uname -r
This will display the kernel version, for example:
2.6.32-754.3.5.el6.x86_64
The kernel version is the first part of the output (2.6.32-754.3.5.el6 in this example).
You can also use the cat command to view the contents of the /proc/version file, which contains the kernel version and other information:
cat /proc/version
This will display output similar to the following:
Linux version 2.6.32-754.3.5.el6.x86_64 (mockbuild@x86-022.build.eng.bos.redhat.com) (gcc version 4.4.7 20120313 (Red Hat 4.4.7-23) (GCC) ) #1 SMP Wed Mar 14 11:17:18 EDT 2018
The kernel version is the first part of the output (2.6.32-754.3.5.el6.x86_64 in this example).