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 $