To find the release and version number of a UNIX operating system, you can use the uname command with the -r flag. The -r flag displays the release number of the operating system, which typically includes the major and minor version numbers.
For example:
$ uname -r 5.4.0-42-generic
In this example, the uname -r command shows that the operating system is running the 5.4 release of the kernel.
Alternatively, you can use the uname command with the -v flag to display the version number of the operating system. The version number typically includes additional information about the patch level and build of the operating system.
For example:
$ uname -v #52~18.04.1-Ubuntu SMP Fri Sep 11 10:06:28 UTC 2020
This command shows that the operating system is running the 18.04.1 version of Ubuntu, with patch level 52 and a build date of September 11, 2020.
It's important to note that the output of the uname command may vary depending on the operating system and version, and it may not provide a complete picture of the operating system release and version. Some operating systems may provide additional tools or commands to display more detailed information about the release and version.