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.\" Copyright 1989 AT&T
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.TH \*(x}
.SH NAME
\f4intro\f1 \- introduction to programming commands
.SH 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:
.PP
.I name
.RI [ option ( s )]
.RI [ cmdarg ( s )]
.PP
where:
.TP 13
.I name
is the name of an executable file.
.TP 13
.I option\^
is 
\f4\-\f2noargletter\f1(\f2s\f1)
or \f4\-\f2argletter <> optarg\f1, 
where:
.sp .4
.I noargletter\^
is a single letter representing an option without an option argument;
.sp .4
.I argletter\^
is a single letter representing an option requiring an option argument;
.sp .4
<> is optional white space;
.sp .4
.I optarg\^
is an option argument (character string) satisfying the preceding
.IR argletter .
.TP 13
.I cmdarg\^
is \f1``\f4\-\f1'' by itself, which indicates the standard input,
or a path name (or other command argument)
.I not\^
beginning with
\f1``\f4\-\f1''.
.PP
Throughout the manual pages there are references to 
\f2TMPDIR, BINDIR, INCDIR, \f1and \f2LIBDIR\f1.
These represent directory names whose value
is specified on each manual page as necessary.
For example, \f2TMPDIR\f1 might refer to \f4/var/tmp\f1.
These are not environment variables and cannot be set.
[There is an environment variable called \f4TMPDIR\f1 which
can be set.  See \f4tmpnam\fP\^(3S).]
There are also references to \f2LIBPATH\f1,
the default search path of the link
editor and other tools.
.SH SEE ALSO
\f4exit\fP(2),
\f4wait\fP(2),
\f4getopt\fP(3C).
.br
\f4getopts\fP(1) in the \f2User's Reference Manual\f1.
.PD 0
.PD
.SH 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
\f4wait\fP(2)
and
\f4exit\fP(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.
.SH 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.
.\"	@(#)intro.1	6.2 of 9/2/83
.Ee
