hacks/bin/rename-videos-by-mtime

#!/bin/bash

set -x

for FN in *.MOV *.MP4 *.MTS *.mov *.mp4; do
    if [[ -e "$FN" ]]; then
        MTIME="$(stat -f "%Sm" "$FN")"
        if [[ ! -z "$MTIME" ]]; then
            # eg "Sep 13 05:02:26 2019"
            NP="$(date -j -f "%b %d %T %Y" "$MTIME" "+%Y-%m-%dT%H%M%S")"
            EXT="${FN##*.}"
            LOWEREXT="$(echo "$EXT" | tr 'A-Z' 'a-z')"
            TARGET="$NP.$LOWEREXT"
            if [[ -e "$FN" ]]; then
                if [[ ! -e "$TARGET" ]]; then
                    mv "$FN" "$TARGET"
                    echo mv "$FN" "$TARGET"
                fi
            fi
        fi
    fi
done