Worth noting that when What died, ~4 new sites popped up immediately and invited all the old members, and everyone raced to re-upload everything from What onto them, which was actually pretty effective. At this point, RED and OPS have greatly surpassed What in many ways, aside from some releases that never made it back (you can actually find out which releases used to exist because What's database was made available after its death). Users and staff are a lot more prepared if it happens again, e.g. keeping track of all metadata via "gazelle-origin".

If by "in" you mean how to get into them, generally you're supposed to have a friend invite you. If you don't have anyone you know on private trackers, you've gotta get in from scratch. Luckily, RED and OPS both do interviews to test your knowledge on the technicals of music formats, though I've heard RED's interview queues are long and OPS's interviews are often just not happening:
interviewfor.red/en/index.html
interview.orpheus.network/

Alternatively, you can interview for MAM, which is IMO the best ebook/audiobook tracker. They're super chill and have a very simple interview e.g. "what is a tracker": myanonamouse.net/inviteapp.php… After that, you can just hang around there for a while until you can get into their recruitment forums to get invites to other entry-level trackers, and then on those entry-level trackers you can get recruited into slightly higher-level trackers, and so on, and eventually RED/OPS should be recruiting from somewhere.

This can feel a little silly and convoluted, but I guess I'd just appreciate that these sites put the effort into conducting interviews for new people at all, since the alternative is that you will just never get into anything without a friend. Reddit's /r/trackers wiki is unfortunately one of the better places for information about private trackers if you want to do further reading.

\#!/bin/bash  

PLAYLIST_URL="$1"  

if [ -z "$PLAYLIST_URL" ]; then  
    echo "Usage: $0 <youtube_playlist_url>"  
    exit 1  
fi  

# Log file with timestamp  
LOG_FILE="$HOME/music-downloads/download_$(date +%Y%m%d_%H%M%S).log"  

echo "Starting download at $(date)" | tee "$LOG_FILE"  
echo "Playlist: $PLAYLIST_URL" | tee -a "$LOG_FILE"  
echo "----------------------------------------" | tee -a "$LOG_FILE"  

# Run sldl with YouTube playlist  
sldl "$PLAYLIST_URL" --yt-dlp 2>&1 | tee -a "$LOG_FILE"  

echo "----------------------------------------" | tee -a "$LOG_FILE"  
echo "Download completed at $(date)" | tee -a "$LOG_FILE"  

Looks like nohup, screen, or tmux are good options.

I've used screen before, it worked well. Though I've never used it to download stuff, it should work the same

Keep processes running after SSH session disconnects

I sometimes have long-running processes that I want to kick off before going home, so I create a SSH session to the server to start the process, but then I want to close my laptop and go home. Later,

^{Unix & Linux Stack Exchange}

I used screen. Just start a screen session for it like "music-downloads" and then you can quit the session and exit out OR install a DE like XFCE on your server and then use something like xfreerdp to remote desktop in, run the script in a terminal on the server, then just close your xfreerdp.

I first used screen to download everything but then decided to install XFCE and Nicotine+ and just leave it up so people can download from my library also.