The uname Command

The uname command reports basic information about a computer's software and hardware.

Its syntax is

uname [options]

When used without any options, uname reports the name, but not the version number, of the kernel (i.e., the core of the operating system). Thus, on a system running some distribution (i.e., version) of Linux, it will display the word Linux on the monitor screen.

The -a (i.e., all) option tells uname to provide the following information: the name of the kernel, network node host name (e.g., localhost.localdomain), kernel version number and release level (e.g., 2.4.20-6), kernel release date, machine hardware name, CPU (central processing unit) type, hardware platform and operating system name (e.g., GNU/Linux).

Options are available to allow each of these pieces of information to be reported individually: -s for kernel name (i.e., the default action), -n for network node host name, -r for kernel version number and release level, -v for date of release of the kernel version, -m for machine hardware name, -p for CPU type (not available on some systems), -i for general hardware platform and -o for operating system.

These options can be combined to produce any combination of output desired, although the order of the output is the same as that provided by the -a option rather than that in which the options are listed. For example, the following will display the kernel name and version number inclusive of the release level:

uname -sr

The output will be in the same order if the options are transposed, i.e.,

uname -rs

The --help option displays brief documentation for uname, and the --version option provides uname's version number.

Created July 13, 2005. Updated June 1, 2006.
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