NAME

intro − introduction to commands and application programs

DESCRIPTION

This section describes, in alphabetical order, commands, including user commands, programming commands, miscellaneous reference information for commands (section 5), and commands used chiefly for maintenance and administration (1M commands). 

Because of command restructuring for the Virtual File System architecture, there are several instances of multiple manual pages with the same name.  For example, there are four manual pages called mount(1M).  In each such case the first of the multiple pages describes the syntax and options of the generic command, that is, those options applicable to all FSTypes (file system types).  The succeeding pages describe the functionality of the FSType-specific modules of the command.  These pages all display the name of the FSType to which they pertain centered and in parentheses at the top of the page.  Note that the administrator should not attempt to call these modules directly.  The generic command provides a common interface to all of them.  Thus the FSType-specific manual pages should not be viewed as describing distinct commands, but rather as detailing those aspects of a command that are specific to a particular FSType. 

Manual Page Command Syntax

Unless otherwise noted, commands described in the SYNOPSIS section of a manual page accept options and other arguments according to the following syntax and should be interpreted as explained below. 

name [−option...] [cmdarg...]
where:

[ ] Surround an option or cmdarg that is not required. 

. . .  Indicates multiple occurrences of the option or cmdarg.

name The name of an executable file. 

option (Always preceded by a “−”.) 
noargletter... or,
argletter optarg[,...]

noargletter A single letter representing an option without an option-argument.  Note that more than one noargletter option can be grouped after one “−” (Rule 5, below). 

argletter A single letter representing an option requiring an option-argument. 

optarg An option-argument (character string) satisfying a preceding argletter. Note that groups of optargs following an argletter must be separated by commas, or separated by white space and quoted (Rule 8, below). 

cmdarg Path name (or other command argument) not beginning with “−”, or “−” by itself indicating the standard input. 

Command Syntax Standard:  Rules

These command syntax rules are not followed by all current commands, but all new commands will obey them.  getopts(1) should be used by all shell procedures to parse positional parameters and to check for legal options.  It supports Rules 3-10 below.  The enforcement of the other rules must be done by the command itself. 

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 “−”. 

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 (for example, −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). 

How to Get Started in the “Introduction” to this document

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

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. 

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.