There are many tools present in the market, you can take help of them.
You can identify which procedures (and other objects with slight modification) are different using the script below.
select S1.name [Db1_Schema], O1.name as [Db1_Object], O1.modify_date,
S2.name [Db1_Schema], O2.name as [Db1_Object], O2.modify_date
from database.sys.all_objects O1
inner join database2.sys.all_objects O2 on O1.name = O2.name
inner join database.sys.syscomments C1 on O1.object_id = C1.id
inner join database2.sys.syscomments C2 on O2.object_id = C2.id
inner join database.sys.schemas S1 on O1.schema_id = S1.schema_id
inner join database2.sys.schemas S2 on O2.schema_id = S2.schema_id
where C1.text <> C2.text and
-- remove the line below if you want to search all objects
O1.type = 'P'