Depending on why you want to turn off all jobs, we usually just stop Sql Server Agent. We would do this if the source server was going to be...

The way I learned some of the s/p's was to right click on the job and choose All tasks...Generate SQL script.  That shows many s/p's used to create a job...

It might be easier to use:

exec msdb..sp_update_job @job_name = 'Job Name', @enabled = 0

Paul (polecki@Insurance.com)