Dos9 is a free software distributed under the GNU GPLv3 terms. This license give you right to run, modify, distribute either modified or verbatim copies of the program, provided that these ones will be distributed under copyleft-compatible license.
To read the whole agreement, see the LICENSE.txt file in your Dos9 directory.
Dos9 - Command prompt and interpreter for windows batch files Copyright (C) 2013 DarkBatcher (Romain Garbi)
This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.
This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA