Job Control Language

Job Control Language (JCL) is a name for scripting languages used on IBM mainframe operating systems. It instructs the system on how to run a batch job or start a subsystem.^[1]

The purpose of JCL is to say which programs to run, using which files or devices ^[2] for input or output. It can indicate under what conditions to skip a step.

There are two distinct IBM Job Control languages:

• one for the operating system lineage that begins with DOS/360 and whose latest member is z/VSE; and
• the other for the lineage from OS/360 to z/OS, the latter now including JES extensions, Job Entry Control Language (JECL).

They share some basic syntax rules and a few basic concepts, but are otherwise very different.