PostgreSQL: How do I export a function definition to SQL

I have a function (stored procedure) defined in a database that I would like to edit.

I think one way of doing this is to dump the function definition to a SQL file, edit the SQL file, then replace the definition in the database with the edited version.

Is it possible to do this (dump the definition to a SQL file)?

What I have been doing in the past is to use psql to connect to the database, run /df+ function, copy the output to a text file, massage the text so it looks like a function declaration, but this is time consuming and I'm wondering if there is a sleeker way of doing it.

I am using PostgreSQL 9.1 if it matters.

EDIT:

I accepted Mike Buland's answer because he provided the correct answer in his comment, which was to run \ef function in psql.