Remove every n frames of gif

frame-count-reduction.sh

#!/bin/bash
# This script will remove every n frames an GIF
# Usage: ./frame-count-reduction.sh input.gif n output.gif

input=$1
divider=$2
output=$3

numOfFrames=eval gifsicle master.gif -I | grep -E -o "[0-9]+ images" | grep -E -o "[0-9]+"
numOfFramesInclusive=$((numOfFrames - 1))

gifsicle $input `
for ((a=0; a <= $numOfFramesInclusive ; a++))
do
  if [ $(($a % $divider)) != 0 ]
    then
      echo "#$a"
  fi
done
` -O3 -o $output