Fabric on mineos? has pretty good info if you have not read it and might want to look at.
Find the base level directory of the server that you want fabric in and cd into it…eg
/var/games/servers/minecraft/thisserver
So run the following commands in the command line
cd /var/games/servers/minecraft/thisserver
curl -OJ https://meta.fabricmc.net/v2/versions/loader/1.19.2/0.14.9/0.11.0/server/jar
Tailor the curl command to your needs after /loader
- minecraft version
- fabric loader version
- installer version
you can also ref these values here Download Minecraft Server Launcher | Fabric