Man appears "nothing appropriate" in Unix system

Recently in a new deployment of the server with MAN-F access to help information when the encounter unexpectedly will be reported "nothing appropriate", then thought it was man did not install and then use Yum installed, the results found that man is installed, so the man Man went to find the option-f parameter to see the next, there is this sentence "equivalent to Whatis." Man-f In fact is the use of Whatis, so use Whatis results found can not use, and then man whatis results found this sentence:

The Whatis database is created using the Command/usr/sbin/makewhatis.

The original man-f is the use of whatis or apropos, of course, these two instructions must be used by the root user, and the use of whatis or apropos must create a Whatis database before running Makewhatis and then using man- F, it looks normal.

This article is from the "Technical essay" blog, please be sure to keep this source http://jim123.blog.51cto.com/4763600/1881553

Man appears "nothing appropriate" in Unix system