If you want a quick and easy way to share the odd file you could set up a syncthing shared folder and COPY things in to it that you want to share. When the other side MOVES them out of the shared folder they will be removed from the shared folder on your side.
The advantage of this is security. No access is given to your system. If your friends box is compromised you dont have an nfs mount or ssh key on their machine. The worst that can be done to you is copies in the shared folder are removed or malicious files are placed in the shared folder but they wont be able to execute.
You also dont need to open any ports for syncthing , it will use relays if it cant make a direct connection.
If you want a quick and easy way to share the odd file you could set up a syncthing shared folder and COPY things in to it that you want to share. When the other side MOVES them out of the shared folder they will be removed from the shared folder on your side.
The advantage of this is security. No access is given to your system. If your friends box is compromised you dont have an nfs mount or ssh key on their machine. The worst that can be done to you is copies in the shared folder are removed or malicious files are placed in the shared folder but they wont be able to execute.
You also dont need to open any ports for syncthing , it will use relays if it cant make a direct connection.