If you want one file per trigger, you can do that from scripting the database. Right-click on the database in Management Studio, select Tasks, Generate Scripts, and then pick the triggers you want to script, and choose one file per object.

If you want a file that will create all your triggers, the query I gave you can do that. Set the output to "File" and run it, or copy-and-paste the results into Notepad, or whatever you want to do to file it. It will give you the create statements for each trigger. You might need to add "GO" between triggers, but that's just a string function.