apropos searches the whatis database and displays the short descriptions of system commands that contain a given string. makewhatis builds the whatis database. It reads all the manual pages in the manpath and for each page writes the name and a short description in the whatis database. man formats and displays the requested on-line manual page. man2dvi converts a manual page into dvi format. man2html converts a manual page into html. whatis searches the whatis database and displays the short descriptions of system commands that contain the given keyword as a separate word.