Tries all variations of Rot# (i.e. Rot13...Rot14...RotN)

rotX.sh

#!/bin/bash
charset=abcdefghijklmnopqrstuvwxyz # Tweak $charset as needed for your alphabet
input=${1,,} #strtolower; greatly simplifies conversion

for char in $(seq 1 ${#charset}); do # Count characters in charset, and for each...
  temp=${charset#?} # Strip the first character, save rest to $temp
  charset=${temp}${charset%"$temp"} # Move the first character of charset behind the rest (abcde becomes bcdea)
  echo $input | tr a-z $charset
done