A sudoku solver

To solve one or more puzzles, run the sudoku command and supply one or more file names as command line arguments:

sudoku file ...

Typically a puzzle will have a single unique solution. However, sudoku will attempt to find and print all solutions. If the puzzle is misconstructed, there may be no solutions at all.

Here is the actual output of the script for an input file named test.puz. The input file is displayed, followed by any solutions found.

========= test.puz =========
5 . .   6 . .   . 8 .
. . 1   5 . 9   2 . .
6 8 .   1 . .   . . .

. 1 9   . . .   . . 7
. . .   9 . 3   . . .
2 . .   . . .   9 5 .

. . .   . . 1   . 2 9
. . 4   3 . 7   5 . .
. 6 .   . . 5   . . 3

--- Solution #1:
5 9 7   6 3 2   1 8 4
3 4 1   5 8 9   2 7 6
6 8 2   1 7 4   3 9 5

4 1 9   2 5 6   8 3 7
8 7 5   9 1 3   6 4 2
2 3 6   7 4 8   9 5 1

7 5 3   8 6 1   4 2 9
1 2 4   3 9 7   5 6 8
9 6 8   4 2 5   7 1 3

Number of solutions found: 1
Elapsed cpu time: 0.52 seconds.