Generating gif files from mov or mp4 in directory of Downloads

gifgen.sh

#!/bin/bash

# This script is going to generate .gif from .MP4 and .mov in the Downloads directory

echo 'Checking tools that are needed in this script...'
# Checking Homebrew for installing ffmpeg
if !(type 'brew' > /dev/null); then
    echo 'Installing Homebrew...'
    /usr/bin/ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"
    if !(type 'brew' > /dev/null); then
        echo "Couldn't install Homebrew." >&2
        exit 1
    fi
fi
# Checking ffmpeg for generating gif file
if !(type 'ffmpeg' > /dev/null); then
    echo 'Installing ffmpeg...'
    brew install ffmpeg
    if !(type 'ffmpeg' > /dev/null); then
        echo "Couldn't install ffmpeg." >&2
        exit 1
    fi
fi

echo 'All green. Will start to generate!'

echo $IFS
IFS_BACKUP=$IFS
IFS=$'\n'
for file in $(find ~/Downloads -maxdepth 1 -name '* *.MP4' -or -name '*.MP4' -or -name '* *.mov' -or -name '*.mov'); do
    if test -e $file.gif; then
        echo "$(basename $file) is passed. Becasue $(basename $file).gif already exists."
    else
        ffmpeg -i $file -vf scale=320:-1 -r 30 $file.gif
    fi
done
IFS=$IFS_BACKUP