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<h2>Variables</h2>
<p>When it is started, <strong>qsh</strong> initializes shell
variables from the defined environment variables. A variable is
used to store data. You can change the value of an existing
variable or create a new variable by using one of these
methods:</p>
<ul>
<li>Assigning a variable using name=value.</li>
<li>Calling the <a href="read.htm">read</a> or <a href="getopts.htm">
getopts</a> utilities.</li>
<li>Using the <em>name</em> parameter in a <strong>for</strong>
loop or <strong>select</strong> conditional construct.</li>
<li>Using the ${name=value} parameter expansion.</li>
<li>Calling the <a href="declare.htm">declare</a> or
<a href="typeset.htm">typeset</a> utilities.</li>
</ul>
<p>Variable names can contain alphabetic characters, numeric
characters, or the underscore (<strong>_</strong>). A variable name
cannot begin with a numeric character.</p>
<h3>Variables set by qsh</h3>
<dl>
<dt><strong>_ (Temporary variable)</strong></dt>
<dd>This variable is set by <strong>qsh</strong> to the last
argument of the previous simple command.</dd>
<dt>
<strong>EGID (Effective primary group identifer)</strong></dt>
<dd>This variable set by <strong>qsh</strong> to the effective primary
group identifier of the process at the time <strong>qsh</strong> is started.
This variable is read-only.</dd>
<dt>
<strong>EUID (Effective user identifer)</strong></dt>
<dd>This variable set by <strong>qsh</strong> to the effective user
identifier of the process at the time <strong>qsh</strong> is started.
This variable is read-only.</dd>
<dt>
<strong>GID (Primary group identifer)</strong></dt>
<dd>This variable set by <strong>qsh</strong> to the primary
group identifier of the process at the time <strong>qsh</strong> is started.
This variable is read-only.</dd>
<dt>
<strong>HOSTID (IP identifier of host)</strong></dt>
<dd>This variable set by <strong>qsh</strong> to the IP address of
the host system.</dd>
<dt>
<strong>HOSTNAME (Name of host)</strong></dt>
<dd>This variable set by <strong>qsh</strong> to the name of
the host system.</dd>
<dt>
<strong>HOSTTYPE (Type of host)</strong></dt>
<dd>This variable set by <strong>qsh</strong> to a string that represents
the type of the host system. The value is set to &quot;powerpc&quot;.
</dd>
<dt><strong>JOBNAME (Qualified job name)</strong></dt>
<dd>This variable is set by <strong>qsh</strong> to the qualified
job name of the current job. The qualified job name is used by CL
commands to identify a job.</dd>
<dt>
<strong>LAST_JOBNAME (Qualified job name of last job)</strong></dt>
<dd>This variable is set by <strong>qsh</strong> to the qualified
job name of the last job it started. The qualified job name is used by CL
commands to identify a job.</dd>
<dt><strong>LINENO (Line number)</strong></dt>
<dd>This variable is set by <strong>qsh</strong> to the current
line number (decimal) in a script or function before it runs each
command.</dd>
<dt>
<strong>MACHTYPE (Machine type)</strong></dt>
<dd>This variable is set by <strong>qsh</strong> to a string that represents the
machine type. The value is set to &quot;powerpc-ibm-os400&quot;.
</dd>
<dt><strong>OLDPWD (Previous working directory)</strong></dt>
<dd>This variable is set by <a href="cd.htm">cd</a> to the previous
working directory after the current working directory is
changed.</dd>
<dt><strong>OPTARG (Option argument)</strong></dt>
<dd>This variable is set by <a href="getopts.htm">getopts</a> when
it finds an option that requires an argument.</dd>
<dt><strong>OPTIND (Option index)</strong></dt>
<dd>This variable is set by <a href="getopts.htm">getopts</a> to
the index of the argument to look at for the next option. The
variable is set to one when <strong>qsh</strong>, a script, or a
function is invoked.</dd>
<dt>
<strong>OSTYPE (Operating system type)</strong></dt>
<dd>This variable set by <strong>qsh</strong> to a string that represents the
operating system type. The value is set to &quot;os400&quot;.
</dd>
<dt><strong>PPID (Parent process ID)</strong></dt>
<dd>This variable is set by <strong>qsh</strong> to the decimal
process ID of the process that invoked the current shell. In a
subshell, the value of the variable is not changed even if the
subshell is running in a different process.</dd>
<dt><strong>PWD (Working directory)</strong></dt>
<dd>This variable is set by <a href="cd.htm">cd</a> to the current
working directory after it is changed.</dd>
<dt><strong>QSH_VERSION (Current version)</strong></dt>
<dd>This variable is set by <strong>qsh</strong> to a string that
represents the current version. The string is in the form VxRyMz
where x is the version number, y is the release number, and z is
the modification number. This variable is read-only.</dd>
<dt><strong>RANDOM (Random number generator)</strong></dt>
<dd>This variable is set by <strong>qsh</strong> to an integer
random number between 1 and 32767 each time it is referenced. You
can seed the random number generator by setting the variable.</dd>
<dt><strong>REPLY (Reply variable)</strong></dt>
<dd>This variable is set by <a href="read.htm">read</a> to the
characters that are read when you do not specify any
arguments and by the select compound command to the contents
of the input line read from standard input.</dd>
<dt><strong>TERMINAL_TYPE (Type of terminal)</strong></dt>
<dd>This variable is set by <strong>qsh</strong> to the type of
terminal attached to the standard file descriptors. The value is
set to &quot;5250&quot; when attached to a 5250 display, to &quot;REMOTE&quot; when
attached to a remote client, or to &quot;PIPELINE&quot; when attached to
pipes.</dd>
<dt><strong>UID (User identifer)</strong></dt>
<dd>This variable set by <strong>qsh</strong> to the user
identifier of the process at the time <strong>qsh</strong> is started.
This variable is read-only.</dd>
</dl>
<h3>Variables used by qsh</h3>
<dl>
<dt><strong>CDPATH (Search path for cd)</strong></dt>
<dd>If the directory you specify for <a href="cd.htm">cd</a> does
not begin with a slash (/), <strong>qsh</strong> searches the
directories listed in <strong>CDPATH</strong> in order for the
specified directory. The value of the variable is a colon separated
list of directories. The current working directory is specified by
a period (.) or a null directory before the first colon, between
two colons, or after the last colon. There is no default
value.</dd>
<dt><strong>ENV (Environment file)</strong></dt>
<dd>When <strong>qsh</strong> is invoked, it performs parameter
expansion, command substitution, and arithmetic expansion on this
variable to generate the path name of a shell script to run in the
current environment. It is typically used to set aliases, define
functions, or set options. There is no default value.</dd>
<dt><strong>HOME (Home directory)</strong></dt>
<dd>The value of this variable is the path name of your home
directory. The value is used for tilde expansion and as the default
argument for <a href="cd.htm">cd</a>. The value is set by default
to the value specified in your user profile.</dd>
<dt><strong>IFS (Internal field separators)</strong></dt>
<dd>The value is a string treated as a list of characters that is
used for field splitting and to split lines into fields with <a
href="read.htm">read</a>. The first character of the value is used
to separate arguments when expanding the <strong>*</strong> special
parameter. The default value is
&quot;&lt;space&gt;&lt;tab&gt;&lt;newline&gt;&quot;.</dd>
<dt><strong>LANG (Language locale)</strong></dt>
<dd>This variable defines the locale category used for categories
that are not specifically set with a variable starting with
<strong>LC_</strong>. There is no default value.</dd>
<dt><strong>LC_ALL (Locale settings)</strong></dt>
<dd>This variable overrides the value of any variables starting
with <strong>LC_.</strong> There is no default value.</dd>
<dt><strong>LC_COLLATE (Locale collation)</strong></dt>
<dd>This variable defines the collation relations between
characters. There is no default value.</dd>
<dt><strong>LC_CTYPE (Locale character classes)</strong></dt>
<dd>This variable defines character types such as upper-case,
lower-case, space, digit and, punctuation. There is no default
value.</dd>
<dt><strong>LC_MESSAGES (Locale message formatting)</strong></dt>
<dd>This variable defines the format and values for affirmative and
negative responses from applications. There is no default
value.</dd>
<dt><strong>LC_MONETARY (Locale monetary formatting)</strong></dt>
<dd>This variable defines the monetary names, symbols, and other
details. There is no default value.</dd>
<dt><strong>LC_NUMERIC (Locale numeric formatting)</strong></dt>
<dd>This variable defines the decimal point character for formatted
input/output and string conversion functions. There is no default
value.</dd>
<dt><strong>LC_TIME (Locale time formatting)</strong></dt>
<dd>This variable defines the date and time conventions, such as
calendar used, time zone, and days of the week. There is no default
value.</dd>
<dt><strong>LC_TOD (Locale time zone)</strong></dt>
<dd>This variable defines the time zone name, time zone difference,
and Daylight Savings Time start and end. There is no default
value.</dd>
<dt><strong>NLSPATH (Search path for message catalogs)</strong></dt>
<dd>When opening a message catalog, the system searches the
directories listed in the order specified until it finds the
catalog. The value of the variable is a colon separated list of
directories. There is no default value.</dd>
<dt><strong>PATH (Search path for commands)</strong></dt>
<dd>If the command you specify does not begin with a slash (/),
<strong>qsh</strong> searches the directories listed in the order
specified until it finds the command to run. The value of the
variable is a colon separated list of directories. The current
working directory is specified by a period (.) or a null directory
before the first colon, between two colons, or after the last
colon. The default value is &quot;/usr/bin:&quot;.</dd>
<dt><strong>PS1 (Primary prompt string)</strong></dt>
<dd>When the interactive option is set, <strong>qsh</strong>
performs parameter expansion, command substitution, and arithmetic
expansion on the variable and displays it on stderr when <strong>
qsh</strong> is ready to read a command. The default value is
&quot;$&quot;.</dd>
<dt><strong>PS2 (Secondary prompt string)</strong></dt>
<dd>When you enter &lt;newline&gt; before completing a command
<strong>qsh</strong> displays the value of this variable on stderr.
The default value is &quot;&gt;&quot;.</dd>
<dt>
<strong>PS3 (Select command prompt)</strong></dt>
<dd>When the <strong>select</strong> compound command is run, <strong>qsh</strong>
performs parameter expansion, command substitution, and arithmetic expansion
on the variable and displays it on stderr to prompt the user to select
one of the choices displayed by <strong>select</strong>. The default value is
&quot;#?&quot;.</dd>
<dt><strong>PS4 (Debug prompt string)</strong></dt>
<dd>When the execution trace option is set and the interactive
option is set, <strong>qsh</strong> performs parameter expansion,
command substitution, and arithmetic expansion on the variable and
displays it on stderr before each line in the execution trace. The
default value is &quot;+&quot;.</dd>
<dt>
<strong>QIBM_CCSID (CCSID for translation)</strong></dt>
<dd>When this variable is set to a numeric value, <strong>
qsh</strong> and various utilities use the value for creating files
and translating data from the CCSID of the job. The default value is &quot;0&quot;
for the default job CCSID. A value of &quot;65535&quot; means no translation is done.
</dd>
<dt><strong>QIBM_CHILD_JOB_SNDINQMSG (Send inquiry message when
child process starts)</strong></dt>
<dd>When this variable is set to a positive numeric value, the
parent process is sent an inquiry message with the qualified job
name of the child process. The child process is held until you
reply the message. By setting this variable, you can debug the
program running in the child process by setting breakpoints before
the program runs. The value of the variable is the level of
descendant processes to debug. When set to 1, child processes are
held, when set to 2 child and grandchild processes are held, etc.
There is no default value.</dd>
<dt><strong>QIBM_MULTI_THREADED (Start multi-thread capable
processes)</strong></dt>
<dd>This variable determines if processes started by <strong>
qsh</strong> can create multiple threads. When the value of the
variable is &quot;Y&quot;, all child processes started by <strong>qsh</strong>
can start threads. The default value is &quot;N&quot;. </dd>
<dt><strong>QSH_REDIRECTION_TEXTDATA (Process data as text for file
redirection)</strong></dt>
<dd>This variable determines if data read from or written to a file
specified on a <a href="redirect.htm">redirection</a> is treated as
text data or binary data. When the value of the variable is &quot;Y&quot;,
<strong>qsh</strong> treats the data read from or written to the
file as text data. When the value of the variable is not &quot;Y&quot;,
<strong>qsh</strong> treats the data read from or written to the
file as binary data. The default value is &quot;Y&quot;.</dd>
<dt><strong>QSH_USE_PRESTART_JOBS (Use pre-start jobs when
available)</strong></dt>
<dd>This variable determines if processes started by <strong>
qsh</strong> use prestart jobs when available. When the value of
the variable is &quot;Y&quot;, <strong>qsh</strong> uses prestart jobs if they
are available in the current subsystem. When the value of the
variable is not &quot;Y&quot;, or prestart jobs are not available, the
processes started by <strong>qsh</strong> are batch immediate jobs.
The default value is &quot;Y&quot;.</dd>
<dt><strong>SHELL (Path name of the shell)</strong></dt>
<dd>When running a script file that does not contain &quot;#!&quot; on the first line,
<strong>qsh</strong> uses the value of this variable as the path name of
the shell interpreter to run the script. There is no default
value.</dd>
<dt><strong>TRACEFILE (Path name of trace file)</strong></dt>
<dd>When the trace option is set, <strong>qsh</strong> uses the
value of this variable as the path name of the file to store the
trace information. The default value is &quot;$HOME/qsh_trace&quot;.</dd>
<dt>
<strong>TRACEOPT (Options for trace file)</strong></dt>
<dd>When the trace option is set, <strong>qsh</strong> uses the
value of this variable to determine how to handle the trace file.
When the value of the variable is &quot;UNLINK&quot;, <strong>qsh</strong>
unlinks the trace file before opening it in a root shell.
When the value of the variable is &quot;KEEP&quot;, <strong>qsh</strong>
keeps the current trace file. The default value is
&quot;UNLINK&quot;.</dd>
</dl>
<h3>Other variables</h3>
<dl>
<dt><img src="delta.gif" alt="Start of change"><strong>QIBM_CMP_FILE_SIZE</strong></dt>
<dd>This variable controls the maximum file size in bytes that <strong>cmp</strong> reads
into an internal buffer for better performance. For files larger than the
maximum size, <strong>cmp</strong> reads the files one byte at a time.
<img src="deltaend.gif" alt="End of change"></dd>
<dt>
<strong>QIBM_OD_OUTPUT_FORMAT (Output format for od)</strong></dt>
<dd>This variable controls the output format for the <a href="od.htm">od</a>
utility. If the value is &quot;OLD&quot;, <strong>od</strong> uses the old
format from previous releases. The old format is not compatible with the current
industry standard and its use is discouraged. There is no default value.
</dd>
<dt><strong>QIBM_QSH_CMD_ESCAPE_MSG (Send escape messages from QSH CL command)</strong></dt>
<dd>This variable controls how messages are sent by the QSH CL command when the
CMD parameter is specified. If the value is
&quot;Y&quot;, the QSH0005 message is sent as an escape message if the exit status is
greater than zero and the QSH0006 and QSH0007 messages are always sent as escape
messages. There is no default value.</dd>
<dt><strong>QIBM_QSH_CMD_OUTPUT (Control output of QSH CL command)</strong></dt>
<dd>This variable controls the output from the QSH CL command when
the CMD parameter is specified. If the value
is &quot;STDOUT&quot;, the output is displayed on the C runtime terminal session. If the
value is &quot;NONE&quot;, the output is discarded. If the value is &quot;FILE&quot;, the output is
written to the specified file. If the value is &quot;FILEAPPEND&quot;, the output is
appended to the specified file. The default value is &quot;STDOUT&quot;.</dd>
<dt>
<strong>QIBM_QSH_INTERACTIVE_CMD (Initial interactive command)</strong></dt>
<dd>When this variable is set to a command string, <strong>qsh</strong> runs the
command when an interactive session is started. The variable must be set
before calling the QSH CL command to have <strong>qsh</strong> run the command.
There is no default value.</dd>
<dt><strong>QIBM_QSH_INTERACTIVE_TYPE (Type of interactive session)</strong></dt>
<dd>This variable sets the type of the interactive session started by the QSH
CL command. If the value is &quot;NOLOGIN&quot;, the interactive session is
not a login session. Otherwise the interactive session is a login session.
There is no default value.</dd>
<dt><strong>QIBM_SYSTEM_ALWMLTTHD (Allow multi-threaded jobs for system)</strong></dt>
<dd>This variable controls how the <a href="system.htm">system</a> utility
behaves in a multi-thread capable job. If the value of the
variable is &quot;Y&quot; and there is only one thread in the job,
<strong>system</strong> runs the CL command in the job. Otherwise, <strong>system</strong>
starts a new job to the run the CL command. There is no default value.</dd>
<dt><strong>QIBM_SYSTEM_USE_ILE_RC</strong></dt>
<dd>Set this environment variable to control how the <a href="system.htm">system</a>
utility sets the exit status. If the value of the variable is &quot;Y&quot;,
<strong>system</strong> sets the exit status to the ILE return code of the
program called by the CL command, or zero if the program did not set a
return code. There is no default value.
</dd>
</dl>
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