whatis looks up a given command and displays the header line from the manual section. You can then run the man(1) command to get more information. If the line starts name(section). . . you can do man –ssection name to get the documentation for it. Try whatis ed and then you should do man –s 1 ed to get the manual page for ed(1).
whatis is actually just the –f option to the man(1) command.
whatis uses the /usr/share/man/man_index/* index files. The index files are either automatically generated by an SMF service as described in man(1) and man(5) or manually generated by using catman (1M) with the –w option. If the index files do not exist, whatis is run slower since it looks directly into manual page files.
Table of Contents and keyword database.
Generated files include:
See attributes(5) for descriptions of the following attributes: