Just execute lsb_release -a.

On Debian:

$ lsb_release -a
No LSB modules are available.
Distributor ID: Debian
Description:    Debian GNU/Linux testing (stretch)
Release:        testing
Codename:       stretch

On Ubuntu:

$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description:    Ubuntu 14.04.4 LTS
Release:        14.04
Codename:       trusty

In case when you don't have lsb_release installed you may want to try some guessing, for example, there is a file /etc/issue that often contains distribution name. For example, on ubuntu:

$ cat /etc/issue
Ubuntu 12.04.5 LTS \n \l

Don't use file /etc/debian_version because its contents do not match distribution name!

Note that this will also work on non-Debian-family distributions like Fedora, RHEL, or openSUSE — but that lsb_release may not be installed.

This method will work on modern versions of Arch, CentOS, CoreOS, Debian, Fedora, Mageia, openSUSE, Red Hat Enterprise Linux, SUSE Linux Enterprise Server, Ubuntu, and others. This wide applicability makes it an ideal as a first approach, with fallback to other methods if you need to also identify older systems.

Look at /etc/os-release. In specific, look at variables NAME, VERSION, ID, VERSION_ID, and PRETTY_NAME.

On Fedora, this file might look like:

   NAME=Fedora
    VERSION="24 (Workstation Edition)"
    ID=fedora
    VERSION_ID=24
    PRETTY_NAME="Fedora 24 (Workstation Edition)"
    ANSI_COLOR="0;34"
    CPE_NAME="cpe:/o:fedoraproject:fedora:24"
    HOME_URL="https://fedoraproject.org/"
    BUG_REPORT_URL="https://bugzilla.redhat.com/"
    REDHAT_BUGZILLA_PRODUCT="Fedora"
    REDHAT_BUGZILLA_PRODUCT_VERSION=24
    REDHAT_SUPPORT_PRODUCT="Fedora"
    REDHAT_SUPPORT_PRODUCT_VERSION=24
    PRIVACY_POLICY_URL=https://fedoraproject.org/wiki/Legal:PrivacyPolicy
    VARIANT="Workstation Edition"
    VARIANT_ID=workstation

On CentOS, this file might look like this:

   NAME="CentOS Linux"
    VERSION="7 (Core)"
    ID="centos"
    ID_LIKE="rhel fedora"
    VERSION_ID="7"
    PRETTY_NAME="CentOS Linux 7 (Core)"
    ANSI_COLOR="0;31"
    CPE_NAME="cpe:/o:centos:centos:7"
    HOME_URL="https://www.centos.org/"
    BUG_REPORT_URL="https://bugs.centos.org/"
    
    CENTOS_MANTISBT_PROJECT="CentOS-7"
    CENTOS_MANTISBT_PROJECT_VERSION="7"
    REDHAT_SUPPORT_PRODUCT="centos"
    REDHAT_SUPPORT_PRODUCT_VERSION="7"

This file is documented on the freedesktop web site (opens new window); in principle, it is not systemd specific — but it will exist on all systemd-based distributions.

From the bash shell, one can source the /etc/os-release file and then use the various variables directly, like this:

$ ( source /etc/os-release && echo "$PRETTY_NAME" )
Fedora 24 (Workstation Edition)

Look at the contents of /etc/redhat-release

cat /etc/redhat-release

Here is the output from a Fedora 24 machine: Fedora release 24 (Twenty Four)

As mentioned in the debian-based response, you can also use the lsb_release -a command, which outputs this from a Fedora 24 machine:

LSB Version:    :core-4.1-amd64:core-4.1-noarch:cxx-4.1-amd64:cxx-4.1-noarch:desktop-4.1-amd64:desktop-4.1-noarch:languages-4.1-amd64:languages-4.1-noarch:printing-4.1-amd64:printing-4.1-noarch
Distributor ID:    Fedora
Description:    Fedora release 24 (Twenty Four)
Release:    24
Codename:    TwentyFour

Uname is the short name for unix name. Just type uname in console to get information about your operating system.

uname [OPTION]

If no OPTION is specified, uname assumes the -s option.

-a or --all - Prints all information, omitting -p and -i if the information is unknown.

Example:

> uname -a

SunOS hope 5.7 Generic_106541-08 sun4m sparc SUNW,SPARCstation-10

All the options:

      |**-s**, **--kernel-name**
      |Print the kernel name.
    

      |**-n**, **--nodename**
      |Print the network node hostname.
    

      |**-r**, **--kernel-release**
      |Print the kernel release.
    

      |**-v**, **--kernel-version**
      |Print the kernel version.
    

      |**-m**, **--machine**
      |Print the machine hardware name.
    

      |**-p**, **--processor**
      |Print the processor type, or "**unknown**".
    

      |**-i**, **--hardware-platform**
      |Print the hardware platform, or "**unknown**".
    

      |**-o**, **--operating-system**
      |Print the operating system.
    

      |**--help**
      |Display a help message, and exit.
    

      |**--version**
      |Display version information, and exit.

just execute uname -a.

On Arch:

$ uname -a
Linux nokia 4.6.4-1-ARCH #1 SMP PREEMPT Mon Jul 11 19:12:32 CEST 2016 x86_64        GNU/Linuxenter code here

Most of linux distros stores its version info in the /etc/lsb-release (debian) or /etc/redhat-release (RPM based) file. Using below generic command should get you past most of the Debian and RPM derivatives as Linux Mint and Cent-Os.

Example on Ubuntu Machine:

cat /etc/*release

DISTRIB_ID=Ubuntu DISTRIB_RELEASE=14.04 DISTRIB_CODENAME=trusty DISTRIB_DESCRIPTION="Ubuntu 14.04 LTS"

So the GNU coreutils should be avaialable on all linux based systems (please correct me if I am wrong here).

If you do not know what system you are using you may not be able to directly jump to one of the examples above, hence this may be your first port of call.

`$ uname -a

On my system this gives me the following...

`Linux Scibearspace 3.16.0-4-amd64 #1 SMP Debian 3.16.7-ckt25-2+deb8u3 (2016-07-02) x86_64 GNU/Linux

Here you can see the following :

Scibearspace : the name of my pc

• Scibearspace : the name of my pc
• 3.16.0-4-amd64 : the kernel and architecture
• SMP Debian 3.16.7-CKT25-2+deb8u3 : tells me I am running debian with the 3.16 kernel
• Finaly the last part I am running debian 8 (update 3).

I would welcome any others to add in results for RHEL, and SuSe systems.

Syntax