I want to get the code used to create an existing procedure by using the command
show create procedure
show create procedure proc_name
You can use the routines table in the information_schema database.
select routine_definition from information_schema.routines where specific_name = 'nameOfYourStoredProcedure'
For more information see this link.
Then you will have to build it yourself. There's no other way.
select CONCAT('CREATE PROCEDURE nameOfYourStoredProcedure ', routine_definition, 'END') /*something like that, this here is pseudo-code*/ from information_schema.routines where specific_name = 'nameOfYourStoredProcedure'
Considering Devart's comment, you will have to also use the parameters table from information_schema database.
Note: This table was added with MySQL 5.5.3
For more information have a look here.
I honestly don't know of any other way to solve this. Also I can't update to 5.5.3 here to help you. Good luck.