Al Aho and I are designing a replacement for grep, egrep and fgrep. The question is what flags should it support and what kind of patterns should it handle? (Assume the existence of flags to make it compatible with grep, egrep and fgrep.) The proposed flags are the V9 flags: -f file pattern is (`cat file`) -v print nonmatching -i ignore aphabetic case -n print line number -x the pattern used is ^pattern$ -c print count only -l print filenames only -b print byte offset of line begin -h do not print filenames in front of matching lines -H always print filenames in front of matching lines -w pattern is <whitespace>pattern<whitespace> -s no output; just status -e expr use expr as the pattern The patterns are as for egrep, supplemented by back-referencing as in \{pattern\}\1. please send your comments about flags or patterns to research!andrew