If I have a slackware or fedora box running one of the things I do post-installation is the makewhatis command as root. Then if I want to search man pages for keywords man -k keyword will search the whole index and it's usually a good idea to pipe through less so you don't loose any potentially interesting entries. slocate -u is another good command to do post-install on these boxes but on debian you'd do the updatedb command and makewhatis isn't necessary since the man pages index aparently gets managed by the debian packaging systems.
