#!/bin/sh

# File Naming Correction (script)
# Usage: fnc [filename]

[ ! -f "$1" ] && { echo "Error: File '$1' not found"; exit 1; }

file="${1##*/}"
dir="${1%/*}"

# lowercase
base=$(echo "${file%.*}" | tr '[:upper:]' '[:lower:]')
ext=$(echo "$file" | grep -q "\." && 
    echo ".${file##*.}" | tr '[:upper:]' '[:lower:]')

# replace whitespaces with single dashes
base=$(echo "$base" | sed 's/\s/-/g;' | tr -s - - |
    # lowercase first letter
    awk '{printf tolower(substr($0,1,1))} {print substr($0,2)}') 

mv -i "$dir/$file" "$dir/$base$ext"