Directs screen output to a file.
If log_path is present, this file has path name log_path and extension “.log”.
If this extension is not present in log_path it will be added. If log_path is absent this file has the root file name of the data
set and the extension ".log".
Screen input is read from a file which has the root name of the data set and the extension ".in".
If a file name has not been defined using the –f command line option and the –log option is used,
it can be entered in the ".in" file.