Thought i share it, since it came in handy lots as a GoG enjoyer.

steamworkshop_dl() {
    steamcmd +login anonymous +workshop_download_item "$1" "$2" validate +quit
    mv -v "<path to your temp Steam folder>/steamapps/workshop/content/"$1"/"$2" "$PWD"/"$3"
}

Purpose: downloading Steam Workshop mod to $PWD with minimal work.

Usage: steamworkshop_dl [game-id] [mod-id] [name]

game-id is in the URL of the main workshop page, mod-id is in the URL of the mod

To make usage simpler, create an alias with the game-id:

alias stdl='steamworkshop_dl <game-id>'
stdl <mod-id> 'that mod'

Needs steamcmd. If download fails, try username and password instead of 'anonymous'.