Each batch job run on the CDC 6500 system produced output on line-printer fan-fold paper. The system produced block letters on the first page with information that the operations staff would use for filing the output. I wrote a program that would produce a second page banner that had more useful filing information for those of us that kept lots of listings.
A typical batch job banner page, though not one from Purdue.
The first few cards of a batch job would have control statements that sequenced the programs run throughout the job. Banner was my program. It produced a page of block letters and then quit to let the job continue.
The control statement interpreter asserted a syntax for commands that included arguments that were typically file names or numeric arguments. There was no provision for passing arbitrary strings.
The unparsed control statement image was passed to a running program. I read that to find string arguments for my command.
BANNER. SPSS V5.6 MM/DD/YY HH:MM:SS
I printed five lines of ten block characters each. The characters could be any in the CDC character set. These would be punched into specific columns of the banner card, 10-19 for the first line, 20-29 for the second line, and so on. I needed no special escapes because my parsing didn't depend on any special characters.
I looked for special lines indicating date and time. For these I substituted the run date and time.