#!/usr/bin/env bash

DIR="/run/media/rasqel/disk/DCIM/101MSDCF"
NUM=1986

for file in "$DIR"/*; do
    [ -f "$file" ] || continue

    name="$(basename "$file")"

    # Не трогаем исходный DSC01985.JPG
    if [ "$name" = "DSC01985.JPG" ]; then
        continue
    fi

    newname=$(printf "DSC%05d.JPG" "$NUM")

    mv -- "$file" "$DIR/$newname"

    echo "$name -> $newname"

    ((NUM++))
done