pi@raspberrypi /usr $ dirhelp *
[games] no information found
[include] no information found
[local] no information found
[share] no information found
[src] no information found
[/bin] Essential command binaries that need to be available in single user mode; for all users, e.g., cat, ls, cp.
[/lib] Libraries essential for the binaries in /bin/ and /sbin/. This directory should hold those shared libraries that are necessary to boot the system and to run the commands in the root file system.
[/sbin] Essential system binaries, e.g., init, ip, mount. Like /bin, this directory holds commands needed to boot the system, but which are usually not executed by normal users.
pi@raspberrypi /usr $ cd share
pi@raspberrypi /usr/share $ dirhelp
[/usr/share] Architecture-independent (shared) data. This directory contains subdirectories with specific application data, that can be shared among different architectures of the same OS. Often one finds stuff here that used to live in /usr/doc or /usr/lib or /usr/man.