In a shell, & is a special character, advising the shell to start everything up to the & as a process in the background. To avoid this behavior, you can put the URL in quotes. See the youtube-dl FAQ for more information.
Also beware of -citk. With the exception of -i, these options make little sense. See the youtube-dl FAQ for more information. Even -f mp4 looks very strange.
So what you want is:
youtube-dl -i -f mp4 –yes-playlist ‘https://www.youtube.com/watch?v=7Vy8970q0Xc&list=PLwJ2VKmefmxpUJEGB1ff6yUZ5Zd7Gegn2’
Alternatively, you can just use the playlist ID:
youtube-dl -i PLwJ2VKmefmxpUJEGB1ff6yUZ5Zd7Gegn2
I found the best solution after many attempts for this problem.
youtube-dl –ignore-errors –format bestaudio –extract-audio –audio-format mp3 –audio-quality 160K –output “%(title)s.%(ext)s” –yes-playlist https://www.youtube.com/playlist?list={your-youtube-playlist-id}