OBS records MKVs right? Well this zips them into one MKV for easy YouTubin'

mkvjoin.sh

#!/bin/bash
# usage: ./mkvjoin.sh "2020-04-03"
# then all recordings in the current dir with that file prefix (PREFIX*.mkv) 
# will be ffmpeg'd into a single mkv stream without conversion so it's fast
#
# usage: ./mkvjoin.sh
# no arg will cause it to use today's date
# tested on macOS 10.15.3 (Catalina) heh

if [ -z "$1 " ]
then
  today=$(date '+%Y-%m-%d')
else
  today=$1
fi
file="$today.txt"

if [ -f "$file" ]; then
  rm $file
fi

touch $file

find $today*.mkv -print0 |
    while IFS= read -r -d '' line; do
      echo "file '$line'" >> $file
    done

cat $file

ffmpeg -f concat -safe 0 -i $file -c copy "$today.mkv"