fnm is a fantastically fast node manager, which make it a pleasure to use over nvm.

fnm handles its own node versions and it observes .node-version files in folder, automatically installing/loading the proper node version.

Part of how it does that:

1. It keeps a user-global installation in $HOME/Library/Application\ Support/fnm, and it’s where it stores the various node versions installed by the user.
2. It creates links to those version in $HOME/.local/state/fnm_multishells, one link per shell.

The side-effect of (2) is that every time you open a shell, a new link is created. And fnm does not clean up when the shell exits. This is by design – so that different shells can have different node versions.
No big deal, but these links can accumulate over time. When I cleaned up my fnm_multishells I had some 3k links in there.

You can clean these up periodically, or you can set a trap EXIT function in zsh and bash to clean it up. Luckily, fnm uses the $FNM_MULTISHELL_PATH to point to the exact sub-folder where the links are created.

Add this to your .zshrc to clean up after fnm.

# fnm creates a bunch of links into $FNM_MULTISHELL_PATH = ~/.local/state/fnm_multishells
# one link per shell instance and it never cleans them up
# this function attempts to do that on shell exit
cleanup_fnm() {
  if [[ -n "$FNM_MULTISHELL_PATH" && -d "$FNM_MULTISHELL_PATH" ]]; then
    rm -rf "$FNM_MULTISHELL_PATH"
  fi
}
trap cleanup_fnm EXIT