Reduce a gif down to a desired number of frames

gif-reduce.sh

#!/usr/bin/env bash

# Reduce a gif down to a desired number of frames.
# Useful for really large gifs that you'd like to truncate.

DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
PROJ_DIR=$(realpath "${DIR}/..")

TEMP_DIR=$(mktemp -d )
REDUCED_DIR=$(mktemp -d)

function cleanup {
  rm -rf "${TEMP_DIR}"
  rm -rf "${REDUCED_DIR}"
}

trap cleanup EXIT

full_gif="${1}"
num_images=${2}
target_name="${3:-${full_gif%.*}-reduced.gif}"

convert "${PROJ_DIR}/${full_gif}" +adjoin ${TEMP_DIR}/temp_%03d.gif

for i in $(seq -w 0 ${num_images}); do
  cp ${TEMP_DIR}/temp_${i}.gif ${REDUCED_DIR}/
done

convert -delay 7 $(ls ${REDUCED_DIR}/*.gif) ${PROJ_DIR}/${target_name}