intro(1) DG/UX 4.30 intro(1)
NAME
intro - introduction to commands and application programs
DESCRIPTION
This section describes, in alphabetical order, publicly-
accessible commands.
COMMAND SYNTAX
Unless otherwise noted, commands described in this section
accept options and other arguments according to the
following syntax:
name [option(s)] [cmdarg(s)]
name The name of an executable file.
option - noargletter(s) or,
- argletter<>optarg
where <> is optional white space.
noargletter A single letter representing an option without
an argument.
argletter A single letter representing an option
requiring an argument.
optarg Argument (character string) satisfying
preceding argletter.
cmdarg Path name (or other command argument) not
beginning with - or, - by itself indicating the
standard input.
Command Syntax Standard: Rules
All new commands will follow the syntax rules below.
Because existing commands have been developed at various
times by various people, some commands will not follow the
rules below. Getopts(1) should be used by all shell
procedures to parse positional parameters and to check for
legal options. Getopts(1) supports Rules 3-10 below. The
command itself must enforce the other rules.
1. Command names (name above) must be between two and
nine characters long.
2. Command names must include only lower-case letters
and digits.
3. Option names (option above) must be one character
long.
4. All options must be preceded by ``-''.
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5. Options with no arguments may be grouped after a
single ``-''.
6. The first option-argument (optarg above) following
an option must be preceded by white space.
7. Option-arguments cannot be optional.
8. Groups of option-arguments following an option
must either be separated by commas or separated by
white space and quoted (e.g., -o xxx,z,yy or -o
"xxx z yy").
9. All options must precede operands (cmdarg above)
on the command line.
10. ``--'' may be used to indicate the end of the
options.
11. The order of the options relative to one another
should not matter.
12. The relative order of the operands (cmdarg above)
may affect their significance in ways determined
by the command with which they appear.
13. ``-'' preceded and followed by white space should
only be used to mean standard input.
SEE ALSO
getopts(1).
exit(2), wait(2), getopt(3C) in the Programmer's Reference
for the DG/UX System
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.
BUGS
Many commands do not adhere to the aforementioned syntax.
WARNINGS
Some commands produce unexpected results when processing
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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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