#!/bin/bash

for file in * ; do
    words=("$file")
    title=""
    wc=0
    for word in $words ; do
    first=$(echo $word | cut -c1 | tr ‘[[:lower:]]’ ‘[[:upper:]]’)
    others=$(echo $word | cut -c2-)
    word="$first$others"
    for prep in {The,A,An,As,At,But,By,For,In,Of,Off,On,Per,To,Up,Via,And,Nor,Or,So,Yet,With}
    do
        if [[ $wc -gt 0 ]] ; then
        if [[ "$word" == "$prep" ]] ; then
            word=`echo "$word" | tr '[A-Z]' '[a-z]'`
        fi
        fi
    done
    title="$title$word"
    title="$title "
    wc=$(($wc + 1))
    done
    #echo "$title"
    mv -- "$file" "$title" > /dev/null 2>&1
done

One thing it DOES NOT do is capitalize last word if it is a preposition which seems to be the rule in all three title case schools (Chicago, MLA and AP), but this does the job in probably 95%~99% cases.