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Sed

Sedoku

This program solves Sudoku puzzles using sed. Puzzles are entered in the following form on the standard input:
..59.43..
4.87.....
.1..8....
2..63..5.
.5.....3.
.8..41..6
....7..2.
.....56.7
..12.34..
with a dot representing an unsolved square, and the result coming out of the standard output. The algorithm works as follows: The sed required to implement this algorithm is explained in the sedoku program.

Edit: Apparently there's a bug and it can't solve some puzzles.
Download: sedoku.sed

99 Green Bottles

You know the song 10 green bottles, and the 99 bottle version commonly song on very long school coach journey's (much to the chagrin of the driver)?

  99 Green bottles hanging on the wall
  99 Green bottles hanging on the wall
  And if one green bottle should accidentally fall...
  98 Green bottles hanging on the wall
  

...and so on.

Well, here is a sed program which will print it out, using either numbers or the names of numbers.

BrainF*@!

I did this to see if sed was Turing complete. BrainF!@k is a minimalist structured language, and it happens to be Turing complete. So if sed can interpret BF programs, then it too must be Turing complete. And it is. The interpreter can only cope with a maximum of 255 loops in the program (it could be adapted to do more, but probably won't be).
Download: brainf__k.sed

FizzBuzz

You never know when you're going to be asked to solve FizzBuzz in an interview. Here's a canned solution for you to present at interview:
s/^$/c_00/
:loop

#Advance the number counter:

#Advance both numbers
h
y/0123456789/1234567890/
x
G

#Keep the 10s only if we've ended in 0
s/...._[0-9]*\([0-9]\)0$/\10/
s/..._[0-9]*\([1-9]\)$/\1/

#Advance the Fizz counter
y/abc/bca/


#Check the fizz and buzz counters and write
#out appropriate text
h
s/c.*/&Fizz/
/[0-9][50]/s/$/Buzz/
s/[^z]*\(..zz.*\)/\1/
s/[abc]_0\?//
p
x

/00/!bloop
D
q

Links

If you're interested in sed, I can recommend the following sites:

If you're interested in advanced sed hackery, then the most impressive programs are:

Updated October 10th 2013, 11:22


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