The Exec class is used to manage command line execution on resources. This class defines options for input, output and error stream handling, and process management including signaling, error and timeout control.
A command’s standard output and error can be redirected to a file, to a stream, to write to the job log, or be discarded. By default, the output is discarded. A command’s standard input can be directed from a file or a stream can be written to. By default, the input is not used.
By default, command line execution is done in behalf of the job user. Exec instances are only allowed during the running of the Joblet class on a resource. The built-in function system() can also be used for simple execution of command lines.