I manually created a .deck file to compile and run a Fortran program with specific data and to create a .log file of all the output, the Fortran program, and the data. I found it to be picky and somewhat hard. So I thought to myself: With something like JCL, one could take simple JCL-like statements, here documents for the source and data files, and programmatically combine them to make a script like the one I created manually.

More Detail::: What SUBMIT Does with Each LJL Statement:

For every statement, SUBMIT generates corresponding commands in the .deck file. Below is a step-by-step breakdown:

One //jo line, as many /dd lines as are required, and as many //ex as are required

//jo sumjob owner=me@mail.com log=print class=a

• Generates a deck command to invoke ifclass a, which checks if the job’s class allows execution at run time.

• Generates a deck command to Log “sumjob is starting” to /var/log/JCL/ with a timestamp.

• Generates a deck command to create /tmp/sumjob

• Generates a deck command to initializes /tmp/sumjob/jobname.log with a formatted header (e.g., via figlet sumjob).

Job Classes: A = Runs as soon as submitted B = Runs only if load is low enough C = Runs in Off-Hours

//dd alias source(here|file=pathandfilename|new) disp(keep|scratch)

• Note the disp (disposition) if keep the put the file in /home/user/.lcl/jobname as whatever the alias is if the disp(scratch) then the file will go into the /tmp/jobname directory as named by the alias.

• Generate deck commands to

– if source is here: copy lines from lcl up to ‘/*’ to the deck file as a here document if source is a file: add commands to copy the file into a working directory either in user’s home or in the tmp directory under the alias. //dd users source(file=/etc/passwd) disp(keep) ==> copy /etc/passwd to /home/user/.ljl/users

//ex somecommand --options < alias

-Generate doc commands to execute the program as specified and save the output to the logfile In this case echo (somecommand --options < aliasproperlyexpanded ) > logfile

The deck file now forms a fully functional batch file to do the specified computation.

Between bash (and the 40 or so other shells available under Linux), python, perl, and the several hundred other scripting languages already available, is a dedicated job control language really needed? I think unnecessary fluff.