Command to check UBUNTU( Diribution -specific release) version

Command is :   

$lsb_release -a
lsb_release -a
No LSB modules are available.
Distributor ID:    Ubuntu
Description:    Ubuntu 12.04.4 LTS
Release:    12.04
Codename:    precise


 $ man lsb_release(1)

NAME
       lsb_release - print distribution-specific information

SYNOPSIS
       lsb_release [options]

DESCRIPTION
       The lsb_release command provides certain LSB (Linux Standard Base) and distribution-specific information.

       If no options are given, the -v option is assumed.

OPTIONS
       The  program  follows  the  usual GNU command line syntax, with long options starting with two dashes (`--').  A summary of
       options are included below.

       -v, --version
              Show the version of the LSB against which your current installation is compliant.  The version  is  expressed  as  a
              colon separated list of LSB module descriptions.

       -i, --id
             Display the distributor's ID.

       -d, --description
              Display a description of the currently installed distribution.

       -r, --release
              Display the release number of the currently installed distribution.

       -c, --codename
              Display the code name of the currently installed distribution.

       -a, --all
              Display all of the above information.

       -s, --short
              Use the short output format for any information displayed.  This format omits the leading header(s).

       -h, --help
              Show summary of options.

NOTES
       This  is  a  reimplementation  of  the  lsb_release  command provided by the Free Standards Group.  Any bugs are solely the
       responsibility of the author below.

       Detection of systems using a mix of packages from various distributions or releases is something of a black art;  the  cur‐
       rent  heuristic  tends  to assume that the installation is of the earliest distribution which is still being used by .B apt
       but that heuristic is subject to error.

SEE ALSO
       lsb(8)

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