cut/join videos using ffmpeg without quality loss

videocj.sh

#!/bin/bash
#cut/join videos using ffmpeg without quality loss

if [ "$(uname)" == "Darwin" ]; then
    if ! [ -x "$(command -v brew)" ]; then
       echo 'homebrew is not installed.'
       /usr/bin/ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"
    fi
    if ! [ -x "$(command -v ffmpeg)" ]; then
       echo 'ffmpeg is not installed.'
       brew install ffmpeg
    fi

elif [ "$(expr substr $(uname -s) 1 5)" == "Linux" ]; then
    if ![ -x "$(command -v ffmpeg)" ]; then
       echo 'ffmpeg is not installed.'
    fi
fi

if [ -z $1 ] || [ -z $2 ]; then
   echo "Usage:$0 c[ut] seconds <File>"
   echo "   eg. $0 c 10 80 example.mp4"
   echo "   eg. $0 c 00:00:10.100 00:01:20.200 example.mp4"
   echo "Usage:$0 j[oin] <FileType>"
   echo "   eg. $0 j avi"
   exit
fi
 
case "$1" in
   c)
      echo "cuttig video..."
      echo $4
      fileName=$(echo $4 | rev | cut -f 2- -d '.' | rev)
      fileType=$(echo $4 | rev | cut -f 1 -d '.' | rev)
      echo $fileName
      echo $fileType
      startTime=$( echo "$2" | tr ':' '_')
      endTime=$( echo "$3" | tr ':' '_' )
      echo $escapedFileName
      ffmpeg -i "$4" -ss $2 -to $3 -acodec copy -vcodec copy "$fileName-$startTime-$endTime.mp4"
      ;;
   j)
      echo "joinning videos..."
      rm temp_list.txt      
      for f in `ls *.$2 | sort -k 1n -t '.'`; do echo "file '$f'" >> temp_list.txt; done
      #printf "file '%s'\n" ./*.$2 > temp_list.txt
      ffmpeg -f concat -i temp_list.txt -c copy output.$2
      rm temp_list.txt
      ;;
   *)
      echo "wrong arguments"
      ;;
esac
exit