executes commands at specified dates and times
according to the instructions in the file
it should only be executed once.
This is best done by running
consists of lines of six fields each.
The fields are separated by spaces or tabs.
The first five are integer patterns to
month of the year (1-12),
and day of the week (1-7 with 1=Monday).
Each of these patterns may
contain a number in the range above;
meaning a range inclusive;
a list of numbers separated by
commas meaning any of the numbers;
or an asterisk meaning all legal values.
The sixth field is a string
that is executed by the Shell at the
in this field is translated to a new-line
Only the first line (up to a % or end of line)
of the command field is executed by the Shell.
The other lines are made available to the
command as standard input.