prepro-cics.pl takes a COBOL program as input, reads it line by line, and output a file with CICS instructions translated.

prepro-cics.pl performs only one pass and processes lines one by one. That is, it reads a line from the standard input, outputs one or several lines (it may output none depending on the output type), and then reads the next input line. This behavior enables it to be compatible for use as a preprocessor inside a compiler, but prohibits using the same file as input and output. Note that it will output lines at the end of the input file.

The preprocessor expects the input COBOL program to have a 6-column left-margin. The output is in fixed format, or an error message should appear.