- display a one-line summary about a keyword
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: