Folders would need to be opened with a file browser like nautilus so you could open them with a command like
If you wanted to run that with a single command you could put it in a script like this
Make it executable
chmod +x /path/to/script
And move it somewhere in your path
mv /path/to/script /home/myaccount/bin
Change the name of the script to whatever command you want to use (choose a name that doesn't clash with something already in your $PATH, or one of the built in shell commands).
Same deal with files, except that you wouldn't open them with nautilus, you'd use whatever was suitable for that file type. For text files, gedit, for example.