\chapentry{Introduction}{1}{1}
\chapentry{Invoking \command {grep}}{2}{1}
\secentry{\sc {gnu} Extensions}{2}{1}{2}
\secentry{Environment Variables}{2}{2}{4}
\chapentry{Diagnostics}{3}{5}
\chapentry{\command {grep} programs}{4}{5}
\chapentry{Regular Expressions}{5}{6}
\chapentry{Usage}{6}{8}
\chapentry{Reporting bugs}{7}{9}
\unnumbchapentry{Concept Index}{10}
\unnumbchapentry{Index}{12}

.