[comp.sys.sgi] How can I see control characters?

HCART@vax.oxford.ac.UK (07/27/89)

    Is there any way that, under vi, one can make visible on the
screen any embedded control characters in a piece of text? I have
a moderately-long piece of Fortran which drives the printer wild
when I try to print it out. It seems to me as though there may be
some hidden character which I may have entered into the document
by mistake which the printer takes as some (unwanted) instruction,
but I can't see it to delete it. Other documents print OK.

    Any ideas?

Thanks,    Hugh Cartwright (HCART@VAX.OXFORD.AC.UK)