uname

Print system information, print information about the machine and operating system it is run on.
If no options are given, 'uname' acts as if the '-s' option were given.

Syntax
      uname [options]...

Options

   -a  --all          Print all of the below information.

   -m  --machine      Print the machine (hardware) type.

   -n  --nodename     Print the machine’s network node hostname.

   -p  --processor    Print the machine’s processor type.

   -r  --kernel-release  Print the kernel release.

   -s  --kernel-name     Print the kernel name.

   -v  --kernel-version   Print the kernel version.

   -i  --hardware-platform Print the hardware platform or "unknown".

   -o  --operating-system  Print the operating system.

If multiple options or '-a' are given, the selected information is printed in this order:

SYSNAME NODENAME RELEASE OSVERSION MACHINE

The full documentation for uname is maintained as a Texinfo manual. If the info and uname programs are properly installed at your site, the command:
info coreutils aquname invocationaq should give you access to the complete manual.

The OSVERSION, at least, might be multiple words.
For example:

$uname -a
=> Linux hayley 1.0.4 #3 Thu May 12 18:06:34 1994 i486

“What’s in a name? That which we call a rose by any other name would smell as sweet” ~ William Shakespeare

Related Linux commands

env - Display, set, or remove environment variables.
groups - Print group names a user is in.
hostname - Print or set system name.
id -un - Print user and group id’s.
logname - Print current login name.
ps - list processes.
tty - Print filename of terminal on stdin.
users - Print login names of users currently logged in.
who - Print who is currently logged in.
whoami - Print the current user id and name.
Equivalent Windows command: ECHO %USERNAME%