intro(1)                         UNIX System V                         intro(1)


NAME
      intro - introduction to programming commands

DESCRIPTION
      This section describes the programming commands in alphabetical order.
      Unless otherwise noted, the commands accept options and other arguments
      according to the following syntax:

      name [option(s)] [cmdarg(s)]

      where:

      name         is the name of an executable file.

      option       is -noargletter(s) or -argletter <> optarg, where:
                   noargletter is a single letter representing an option
                   without an option argument;
                   argletter is a single letter representing an option
                   requiring an option argument;
                   <> is optional white space;
                   optarg is an option argument (character string) satisfying
                   the preceding argletter.

      cmdarg       is ``-'' by itself, which indicates the standard input, or a
                   path name (or other command argument) not beginning with
                   ``-''.

      Throughout the manual pages there are references to TMPDIR, BINDIR,
      INCDIR, and LIBDIR.  These represent directory names whose value is
      specified on each manual page as necessary.  For example, TMPDIR might
      refer to /var/tmp.  These are not environment variables and cannot be
      set.  [There is an environment variable called TMPDIR which can be set.
      See tmpnam(3S).]  There are also references to LIBPATH, the default
      search path of the link editor and other tools.

SEE ALSO
      exit(2), wait(2), getopt(3C)
      getopts(1) in the User's Reference Manual.

DIAGNOSTICS
      Upon termination, each command returns two bytes of status, one supplied
      by the system and giving the cause for termination, and (in the case of
      ``normal'' termination) one supplied by the program [see wait(2) and
      exit(2)].  The former byte is 0 for normal termination; the latter is
      customarily 0 for successful execution and non-zero to indicate troubles
      such as erroneous parameters, or bad or inaccessible data.  It is called
      variously ``exit code,'' ``exit status,'' or ``return code,'' and is
      described only where special conventions are involved.

NOTES
      Some commands produce unexpected results when processing files containing
      null characters.  These commands often treat text input lines as strings


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intro(1)                         UNIX System V                         intro(1)


      and therefore become confused upon encountering a null character (the
      string terminator) within a line.




















































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