At submit time, you can specify the command interpreter to use to process the job script file. See, for example, Figure 3–5. However, if nothing is specified, the configuration variable shell_start_mode determines how the command interpreter is selected:
If shell_start_mode is set to unix_behavior, the first line of the script file specifies the command interpreter. The first line of the script file must begin with #!. If the first line does not begin with #!, the Bourne Shell sh is used by default.
For all other settings of shell_start_mode, the default command interpreter is determined by the shell parameter for the queue where the job starts. See Displaying Queues and Queue Properties and the queue_conf(5) man page.