How we can back up all databases in SQL Server

USE master
GO
SET NOCOUNT ON

DECLARE @BackupPath nvarchar(500)
DECLARE @BackupDBFile nvarchar(500)
DECLARE @BackupLogFile nvarchar(500)
DECLARE @FolderName nvarchar(25)
DECLARE @ShellPath nvarchar(500)
DECLARE @DatabaseName nvarchar(25)
DECLARE @BackupDBDevice  nvarchar(25)
DECLARE @BackupLogDevice  nvarchar(25)

SET @BackupPath = 'C:\'

-- Create datetime folder for backup files
SELECT @FolderName = CONVERT( nvarchar(8),GETDATE(),112)+'_'+REPLACE(CONVERT( nvarchar(8),GETDATE(),8),':','')
SET @ShellPath = 'md ' + @BackupPath + @FolderName
SET @BackupPath = @BackupPath + @FolderName
exec master..xp_cmdshell @ShellPath , NO_OUTPUT

-- Declare Cursor
DECLARE CUR_BackupDB CURSOR FOR
select name from sysdatabases
--where name = 'master'
where name not in ('tempdb','pubs','Northwind')

-- Open Cursor
OPEN CUR_BackupDB

-- Fetch the db names from Cursor
FETCH NEXT FROM CUR_BackupDB INTO @DatabaseName

WHILE @@FETCH_STATUS = 0
BEGIN
 SET @BackupDBDevice  = @DatabaseName + '_data_dev'
 SET @BackupLogDevice  = @DatabaseName + '_log_dev'
 SET @BackupDBFile  = @BackupPath + '\' + @DatabaseName + '_data.dat'
 SET @BackupLogFile  = @BackupPath + '\' + @DatabaseName + '_log.dat'

 -- Create the backup device for the full db backup.
 EXEC sp_addumpdevice 'disk',  @BackupDBDevice, @BackupDBFile
 
 --Create the log backup device.
 EXEC sp_addumpdevice 'disk',  @BackupLogDevice, @BackupLogFile
 
 -- Back up the full database .
 BACKUP DATABASE @DatabaseName TO @BackupDBDevice
 
 IF( @DatabaseName != 'master' )
  -- Back up the log of the database .
  BACKUP LOG @DatabaseName TO @BackupLogDevice

 -- Drop dump device
 EXEC sp_dropdevice @BackupDBDevice
 EXEC sp_dropdevice @BackupLogDevice

 -- Fetch the db names from Cursor
 FETCH NEXT FROM CUR_BackupDB INTO @DatabaseName
END

-- Distroy Cursor
CLOSE CUR_BackupDB
DEALLOCATE CUR_BackupDB

SET NOCOUNT OFF