Το πρόγραμμα βοηθείας

Παράδειγμα:

athena:~> apropos topological
tsort (1)            - Topological sort of a directed graph

athena:~> man tsort 

TSORT(1)                     UNIX Reference Manual                    TSORT(1)

NAME
     tsort - topological sort of a directed graph

SYNOPSIS
     tsort [file]

DESCRIPTION                                           
...