Script to convert and join a directory of youtube-dl flv files from Twitch to mp4 for upload/archiving to YouTube

twitch2mp4.sh

#!/bin/bash

function join { local IFS="$1"; shift; echo "$*"; }

outfile="$(basename "$(ls -1 *.flv|head -1)" .flv).mp4"
if [ ! -f outfile ]; then
  i=0
  lnfiles=()
  for j in *.flv; do
    echo $j
    targetfile="file$i.flv"
    ln -sv "$j" $targetfile
    lnfiles[$i]=$targetfile
    i=$(($i+1))
  done
  declare -p lnfiles
  ffmpeg -n -i "concat:$(join "|" ${lnfiles[@]})" -threads 0 "$outfile"
  for lnfile in "${lnfiles[@]}"; do
    rm -v $lnfile
  done
else
  echo $outfile exists, skipping
fi