Happy birthday in bash
Usage: hbd.sh [NAME] [AGE]
Requirements: GNU Bash
POSIX bc (preferably GNU bc)
hbd.sh is licensed under the Eiffel Forum License version 2.
hbdmusic.sh and korobeiniki.sh are licensed under the
GNU General Public License version 3 or (at your option) any
later version published by the Free Software Foundation.
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.