Create a symbolic link of directory in Ubuntu

In script is useful something like this:

if [ ! -d /etc/nginx ]; then ln -s /usr/local/nginx/conf/ /etc/nginx > /dev/null 2>&1; fi

it prevents before re-create "bad" looped symlink after re-run script

This is the behavior of ln if the second arg is a directory. It places a link to the first arg inside it. If you want /etc/nginx to be the symlink, you should remove that directory first and run that same command.

That's what ln is documented to do when the target already exists and is a directory. If you want /etc/nginx to be a symlink rather than contain a symlink, you had better not create it as a directory first!