The Orac-dr infrastructure provides commands for primitive writers to print informational messages,
warnings and error messages to the user. These commands are orac_print, orac_say, orac_warn, and
orac_err. In principal these commands can send information to different locations and this location is
under the control of the person running the pipeline rather than primitive writer (using the -log
option). The Perl print and warn commands should not be used since they always write output to
standard output and standard error whereas the ORAC print commands can send to multiple
filehandles.