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 [OPTION]...

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'
`--release'
     Print the operating system release.

`-s'
`--sysname'
     Print the operating system name.

`-v'
     Print the operating system version.

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

SYSNAME NODENAME RELEASE OSVERSION MACHINE

The OSVERSION, at least, may well be multiple words.
For example:
uname -a
=> Linux hayley 1.0.4 #3 Thu May 12 18:06:34 1994 i486

Related commands:

env - Display, set, or remove environment variables
groups - Print group names a user is in
hostname - Print or set system name
id - 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 (`id -un')