Here's a clever idea, what if we detected if the script was run via shebang or pipe? This works on my system;

``` sh
#!/bin/zsh
if [ -n "$1" ]; then
  exec <"$1"
elif tty >/dev/null; then
  echo 'file'
else
  echo "pipe"
fi
```

Then if the script is run via shebang we can assume it's already installed and just do the linking of the rc files.