🧪 Bash Week — Hamming Distance Spell (Char-by-Char Comparison, Final Form)
It calculates the Hamming distance (number of differing characters) between two equal-length strings.
Bash Spell:
#!/usr/bin/env bash
if [[ $# -ne 2 ]]; then
echo "Usage: $0 <string1> <string2>"
exit 1
elif [[ ${#1} -ne ${#2} ]]; then
echo "strands must be of equal length"
exit 1
else
count=0
for ((i = 0; i < ${#1}; i++)); do
a="${1:$i:1}"
b="${2:$i:1}"
if [[ "$a" != "$b" ]]; then
((count++))
fi
done
echo "$count"
fi
Notes:
- Input validation ensures exactly two args and equal string length.
- Uses Bash string slicing to compare characters by index.
- Avoids off-by-one or miscounting bugs from early exits.
- Ideal for scripting challenges, interviews, or shell-based logic tasks.