cat ph-vig.txt | ./letPair -n X

and look for spikes at multiples of K.

For -o X going from 1 to K,

cat ph-vig.txt | ./format -m K -o X | ./letFreq

count _back_ a, b, c, d, _e_ from a peak, starting on peak.
this might be the shift letter for vigenere -d.


cat ph-vig.txt | ./vigenere -d {k_1}{k_2}...

to test key as yo go.