doc {<subject> ... <subject>}
    Attempt to print out a doc file on the given subject(s). Note that doc
    files are normally considerably longer than help files. They were made
    available on-line because it was easy to do so - it is recommended that
    you get a printed version of the doc files. The hosting system may not
    have all doc files (or all help files for that matter) on line. The
    printout can be aborted with a control-C.
Doc: intro, communication, economics, society, sectors, ships, weather,
    aircraft, war
Help: help