4.3BSD - /usr/man/cat1/intro.0

INTRO(1)                                                              INTRO(1)


NAME
       intro - introduction to commands

DESCRIPTION
       This  section  describes  publicly  accessible  commands  in alphabetic
       order.  Certain distinctions of purpose are made in the headings:

       (1)    Commands of general utility.

       (1C)   Commands for communication with other systems.

       (1G)   Commands used primarily for graphics and computer-aided  design.

       N.B.:  Commands related to system maintenance used to appear in section
       1 manual pages and were distinguished by (1M) at the top of  the  page.
       These manual pages now appear in section 8.

SEE ALSO
       Section (6) for computer games.

       How to get started, in the Introduction.

DIAGNOSTICS
       Upon termination each command returns two bytes of status, one supplied
       by the system giving the cause for termination, and  (in  the  case  of
       ‘normal’  termination)  one  supplied  by  the  program,  see  wait and
       exit(2).  The former byte is 0 for normal termination,  the  latter  is
       customarily  0  for  successful execution, nonzero to indicate troubles
       such as erroneous  parameters,  bad  or  inaccessible  data,  or  other
       inability  to cope with the task at hand.  It is called variously ‘exit
       code’, ‘exit status’ or ‘return code’, and is described only where spe‐
       cial conventions are involved.


7th Edition                     April 29, 1985                        INTRO(1)