apt-get install fortunes

/usr/games/fortune  # return a fortune cookie (fetches a random sentence (% separated lines) from a random file in /usr/share/games/fortunes/ )
/usr/games/fortune PATH/FILE  # return a fortune cookie fetching a random sentence (% separated lines) from the given FILE

To create your own fortune files:

Create a text file separating each fortune cookie with lines containing only a percent (%) sign.
Create a database file for that text file, with the same file name followed by a .dat extension, and place it in the same directory: strfile PATH/FILENAME PATH/FILENAME.dat