Known Problems with some *roff versions
If you encounter the error:
Unknown escape sequence in input: 33, 133
when trying to create op.txt then set the GROFF_NO_SGR environment
variable (see grotty(1) man page), e.g.,
csh% setenv GROFF_NO_SGR 1
sh$ GROFF_NO_SGR=1; export GROFF_NO_SGR
$Id: README,v 8.1 2004-07-20 20:25:10 ca Exp $