Shell script to batch convert HEIC files to jpeg, leaving the original and its converted side by side. Requires Mac OS or Linux, the find command line tool, and ImageMagick

batch-convert-heic.rb

#!/usr/bin/env ruby

require 'shellwords'

files = `find . -iname '*.heic'`.split("\n")
files.each do |original_file|
  output_file = original_file.gsub(/\.heic\z/i, ' Converted.jpg')
  if File.exist?(output_file)
    STDERR.puts "Skipping output #{output_file} exists."
  else
    cmd = "convert #{Shellwords.escape(original_file)} #{Shellwords.escape(output_file)}"
    puts cmd
    system cmd
  end
en

or without needing Ruby on Linux ( and perhaps OS X with brew ):

sudo apt-get install libheif-examples # ( install the library )
for i in *.heic; do heif-convert "$i" "${i%.*}.jpg"; done