intro(1)                                                 intro(1)



     NAME
          intro - introduction to commands and application programs

     DESCRIPTION
          This section describes, in alphabetical order, publicly-
          accessible commands.  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.
          (1N)  Network commands.

     COMMAND SYNTAX
          Unless otherwise noted, commands described in this section
          accept options and other arguments according to the
          following syntax:

          name [arg(s)] [cmdarg(s)] ...

          where:

          name          is the command name (the name of an executable
                        file);

          arg can be:
                             -noargletter(s),
                             (a single letter representing an option
                             without an argument); or

                             -argletter <>optarg
                             (where -argletter is a single letter
                             representing an option that requires an
                             argument, <> is optional white space, and
                             optarg is an argument (character string)
                             satisfying the preceding -argletter.

          []            indicates an optional argument.

          cmdarg        is a metasymbol indicating a pathname (or
                        other command argument) that does not begin
                        with - or, - by itself (indicating the
                        standard input).

          ...           indicates that arguments may be repeated any
                        number of times.

     SEE ALSO
          The SEE ALSO sections of the manual pages refer to other
          relevant documentation.




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     intro(1)                                                 intro(1)



     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, 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 special
          conventions are involved.

     WARNINGS
          Some commands produce unexpected results when processing
          files containing null characters.  These commands often
          treat text input lines as strings and therefore become
          confused upon encountering a null character (the string
          terminator) within a line.




































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