I'm sure there are many ways to skin this cat. Initial approaches:

In SSMS, i would query sys.sql_modules and paste the query results into a single file.

select sm.definition

from sys.sql_modules sm

inner join sys.objects so on sm.object_id = so.object_id

where so.type = 'p'

order by sm.object_id;

In the file system, I would use the type command to consolidate them into one file.

type *.sql > consolidated.sql