datemath is a script for some simple math operations on dates in bash.
scakko@link:~/bin$ date
Sat Jun 6 01:54:53 CEST 2009
scakko@link:~/bin$ ./datemath +1D
Sun Jun 07 2009
scakko@link:~/bin$ ./datemath -1W
Sat May 30 2009
scakko@link:~/bin$ ./datemath +1M
Mon Jul 06 2009
scakko@link:~/bin$ ./datemath -1Y
Fri Jun 06 2008
