Installing SQL Server 2012 in unattended mode using command line and configuration file

1-Create cmd file  with below highlighted text and save it as c:\SQLCMDInstaller\InstallSQL.CMD

<SQL media>l\setup.exe /Configurationfile="ConfigurationFile.ini" /IAcceptSQLServerLicenseTerms

replace the <SQL media> with the path where you have your SQL media.

2-Create ConfigurationFile.ini file below with the highlighted text below, and saved it in  c:\SQLCMDInstaller\

Configure the parameters highlighted in green

those are 

1. Features to be installed.
2. AS SYS Admin account.
3. SQL SYS Admin account.
4. Instance name.

;SQL SERVER 2012 Configuration File
[OPTIONS]

; Specifies a Setup work flow, like INSTALL, UNINSTALL, or UPGRADE. This is a required parameter. 

ACTION="Install"

; Detailed help for command line argument ROLE has not been defined yet. 

ROLE="AllFeatures_WithDefaults"

; Detailed help for command line argument ENU has not been defined yet. 

ENU="True"

; Setup will not display any user interface. 

QUIET="True"

; Specify whether SQL Server Setup should discover and include product updates. The valid values are True and 
False or 1 and 0. By default SQL Server Setup will include updates that are found. 

UpdateEnabled="True"

; Specifies features to install, uninstall, or upgrade. The list of top-level features include SQL, AS, RS, IS, 
MDS, and Tools. The SQL feature will install the Database Engine, Replication, Full-Text, and Data Quality 
Services (DQS) server. The Tools feature will install Management Tools, Books online components, SQL Server 
Data Tools, and other shared components. 

   FEATURES=SQLENGINE,REPLICATION,FULLTEXT,DQ,AS,RS,DQC,BIDS,CONN,IS,BC,SDK,BOL,SSMS,ADV_SSMS,SNAC_SDK,MDS

; Specifies the list of administrator accounts that need to be provisioned. 

ASSYSADMINACCOUNTS="<ASSYSADMINACCOUNT>"

; Windows account(s) to provision as SQL Server system administrators. 

SQLSYSADMINACCOUNTS="<SYSADMINACCOUNT>"

; Specify that SQL Server feature usage data can be collected and sent to Microsoft. Specify 1 or True to 
enable and 0 or False to disable this feature. 

SQMREPORTING="False"

; Specify if errors can be reported to Microsoft to improve future SQL Server releases. Specify 1 or True to 
enable and 0 or False to disable this feature. 

ERRORREPORTING="FALSE"

; Specify a default or named instance. MSSQLSERVER is the default instance for non-Express editions and 
SQLExpress for Express editions. This parameter is required when installing the SQL Server Database Engine 
(SQL), Analysis Services (AS), or Reporting Services (RS). 

INSTANCENAME="MSSQLSERVER"

; RSInputSettings_RSInstallMode_Description 

RSINSTALLMODE="FilesOnlyMode"

; Don't provision current user as a Database Engine system administrator.

ADDCURRENTUSERASSQLADMIN="False"

3-Run cmd prompt as Administrator, change the prompt to  c:\SQLCMDInstaller\

run  InstallSQL.CMD

P.S.

this will install SQL as evaluation sku, to specify required sku, PID setting needs to be specified in the configuration file.