ch04_03.htm

unix基础教程

PATH search.</p>
</td></tr>
<tr><td><p><tt class="literal">$</tt><em class="replaceable"><tt>n</tt></em></p>
</td><td><p>Individual arguments on command line (positional parameters).
The Bourne shell allows only nine parameters to be referenced
directly (<em class="emphasis">n</em> = 1&#8211;9);
the Korn shell allows <em class="emphasis">n</em> to be
greater than 9 if specified
as <tt class="literal">${</tt><em class="replaceable"><tt>n</tt></em><tt class="literal">}</tt>.</p>
</td></tr>
<tr><td><p><tt class="literal">$*</tt>, <tt class="literal">$@</tt></p>
</td><td><p>All arguments on command line (<tt class="literal">$1 $2</tt> ...).</p>
</td></tr>
<tr><td><p><tt class="literal">"$*"</tt></p>
</td><td><p>All arguments on command line as one string
(<tt class="literal">"$1&#160;$2..."</tt>).</p>
</td></tr>
<tr><td><p><tt class="literal">"$@"</tt></p>
</td><td><p>All arguments on command line, individually quoted
(<tt class="literal">"$1" "$2"</tt> ...).</p>
</td></tr>
</table><p>
<p>The Korn shell automatically sets these additional variables:</p>

<table border="1" cellpadding="3">



<tr><td><p><tt class="literal">$_</tt></p>
</td><td><p>Temporary variable; initialized to pathname of script or program being
executed.  Later, stores the last argument of previous command.  Also
stores name of matching MAIL file during mail checks.</p>
</td></tr>


<tr><td><p><tt class="literal">LINENO</tt></p>
</td><td><p>Current line number within the script or function.
<a name="IXT-4-122712" /></p>
</td></tr>
<tr><td><p><tt class="literal">OLDPWD</tt></p>
</td><td><p>Previous working directory (set by <tt class="literal">cd</tt>).
<a name="IXT-4-122713" /></p>
</td></tr>
<tr><td><p><tt class="literal">OPTARG</tt></p>
</td><td><p>Name of last option processed by <tt class="literal">getopts</tt>.
<a name="IXT-4-122714" /></p>
</td></tr>
<tr><td><p><tt class="literal">OPTIND</tt></p>
</td><td><p>Numerical index of OPTARG.
<a name="IXT-4-122715" /></p>
</td></tr>
<tr><td><p><tt class="literal">PPID</tt></p>
</td><td><p>Process number of this shell's parent.
<a name="IXT-4-122716" /></p>
</td></tr>
<tr><td><p><tt class="literal">PWD</tt></p>
</td><td><p>Current working directory (set by <tt class="literal">cd</tt>).
<a name="IXT-4-122717" /></p>
</td></tr>
<tr><td><p><tt class="literal">RANDOM</tt>[<tt class="literal">=</tt><em class="replaceable"><tt>n</tt></em>]</p>
</td><td><p>Generate a new random number with each reference;
<a name="IXT-4-122718" />
start with integer <em class="emphasis">n</em>, if given.</p>
</td></tr>
<tr><td><p><tt class="literal">REPLY</tt></p>
</td><td><p>Default reply, used by <tt class="literal">select</tt> and <tt class="literal">read</tt>.
<a name="IXT-4-122719" /></p>
</td></tr>
<tr><td><p><tt class="literal">SECONDS</tt>[<tt class="literal">=</tt><em class="replaceable"><tt>n</tt></em>]</p>
</td><td><p>Number of seconds since the shell was started,
<a name="IXT-4-122720" />
or, if <em class="emphasis">n</em> is given, number of seconds + <em class="emphasis">n</em>
since the shell started.</p>
</td></tr>
</table><p>
<p><tt class="literal">ksh93</tt>
automatically sets these additional variables.
Variables whose names contain &#8220;.&#8221; must be enclosed
in braces when referenced, e.g., <tt class="literal">${.sh.edchar}</tt>.</p>

<table border="1" cellpadding="3">

<tr><td><p><tt class="literal">HISTCMD</tt></p>
</td><td><p>The history number of the current command.</p>
</td></tr>
<tr><td><p>
<a name="IXT-4-122721" /><tt class="literal">.sh.edchar</tt></p>
</td><td><p>The character(s) entered when processing a <tt class="literal">KEYBD</tt>
trap.  Changing it replaces the characters that caused the trap.</p>
</td></tr>
<tr><td><p><tt class="literal">.sh.edcol</tt></p>
</td><td><p>The position of the cursor in the most recent
<tt class="literal">KEYBD</tt>
trap.</p>
</td></tr>
<tr><td><p><tt class="literal">.sh.edmode</tt></p>
</td><td><p>Will be equal to ESCAPE if in a <tt class="literal">KEYBD</tt>
trap in <tt class="literal">vi</tt> mode, otherwise empty.</p>
</td></tr>
<tr><td><p><tt class="literal">.sh.edtext</tt></p>
</td><td><p>The characters in the input buffer during
a <tt class="literal">KEYBD</tt> trap.</p>
</td></tr>
<tr><td><p><tt class="literal">.sh.name</tt></p>
</td><td><p>The name of the variable running a discipline function.</p>
</td></tr>
<tr><td><p><tt class="literal">.sh.subscript</tt></p>
</td><td><p>The subscript of the variable running a discipline function.</p>
</td></tr>
<tr><td><p><tt class="literal">.sh.value</tt></p>
</td><td><p>The value of the variable inside the <tt class="literal">set</tt>
and <tt class="literal">get</tt> discipline functions.</p>
</td></tr>
<tr><td><p><tt class="literal">.sh.version</tt></p>
</td><td><p>The version of <tt class="literal">ksh93</tt>.</p>
</td></tr>
</table><p>
</div>

<a name="unut-ch-4-sect-3.3" /><div class="sect2"><h3 class="sect2">4.3.3. Other Shell Variables</h3><p>The following variables are not automatically set by the shell.
They are typically used in your <tt class="literal">.profile</tt> file,
where you can define them to suit your needs.
Variables can be assigned values by issuing commands of the form:</p>

<blockquote><pre class="code"><em class="replaceable"><tt>variable</em>=<em class="replaceable">value</tt></em></pre></blockquote>
<p>This list includes the type of value expected when defining
these variables.
Those that are specific to the Korn shell are marked as (K).
Those that are specific to <tt class="literal">ksh93</tt> are marked (K93).</p>

<table border="1" cellpadding="3">

<tr><td><p><tt class="literal">CDPATH=</tt><em class="replaceable"><tt>dirs</tt></em></p>
</td><td><p>Directories searched by <tt class="literal">cd</tt>;
allows shortcuts in changing directories;
unset by default.</p>
</td></tr>
<tr><td><p>
<a name="IXT-4-122722" /><tt class="literal">COLUMNS=</tt><em class="replaceable"><tt>n</tt></em></p>
</td><td><p>(K) Screen's column width; used in line edit modes and <tt class="literal">select</tt> lists.
<a name="IXT-4-122723" /></p>
</td></tr>
<tr><td><p><tt class="literal">EDITOR=</tt><em class="replaceable"><tt>file</tt></em></p>
</td><td><p>(K) Pathname of line edit mode to turn on
<a name="IXT-4-122724" />
<a name="IXT-4-122725" />
(can end in <tt class="literal">emacs</tt> or <tt class="literal">vi</tt>);
used when VISUAL is not set.</p>
</td></tr>
<tr><td><p><tt class="literal">ENV=</tt><em class="replaceable"><tt>file</tt></em></p>
</td><td><p>(K) Name of script that gets executed at startup;
<a name="IXT-4-122726" />
useful for storing alias and function definitions.
For example, <tt class="literal">ENV=$HOME/.kshrc</tt>
(like C shell's <tt class="literal">.cshrc</tt>).</p>
</td></tr>
<tr><td><p><tt class="literal">FCEDIT=</tt><em class="replaceable"><tt>file</tt></em></p>
</td><td><p>(K) Editor used by <tt class="literal">fc</tt> command (default is <tt class="literal">/bin/ed</tt>).


Obsoleted in <tt class="literal">ksh93</tt> by HISTEDIT.
<a name="IXT-4-122727" /></p>
</td></tr>
<tr><td><p><tt class="literal">FIGNORE=</tt><em class="replaceable"><tt>pattern</tt></em></p>
</td><td><p>(K93) Pattern describing the set of filenames to ignore during
pattern matching.
<a name="IXT-4-122728" /></p>
</td></tr>
<tr><td><p><tt class="literal">FPATH=</tt><em class="replaceable"><tt>dirs</tt></em></p>
</td><td><p>(K) Directories to search for function definitions;
<a name="IXT-4-122729" />
undefined functions are set via <tt class="literal">typeset -fu</tt>;
FPATH is searched when these functions are first referenced.
(<tt class="literal">ksh93</tt> also searches PATH.)</p>
</td></tr>
<tr><td><p><tt class="literal">HISTEDIT=</tt><em class="replaceable"><tt>file</tt></em></p>
</td><td><p>(K93) Editor used by <tt class="literal">hist</tt> command, if
set.  Overrides the setting of FCEDIT.
<a name="IXT-4-122730" /></p>
</td></tr>
<tr><td><p><tt class="literal">HISTFILE=</tt><em class="replaceable"><tt>file</tt></em></p>
</td><td><p>
<a name="IXT-4-122731" />(K) File in which to store command history
(must be set before <tt class="literal">ksh</tt> is started);
default is <tt class="literal">$HOME/.sh_history</tt>.</p>
</td></tr>
<tr><td><p><tt class="literal">HISTSIZE=</tt><em class="replaceable"><tt>n</tt></em></p>
</td><td><p>
<a name="IXT-4-122732" />(K) Number of history commands available
(must be set before <tt class="literal">ksh</tt> is started);
default is 128.</p>
</td></tr>
<tr><td><p><tt class="literal">HOME=</tt><em class="replaceable"><tt>dir</tt></em></p>
</td><td><p>
<a name="IXT-4-122733" />Home directory; set by <tt class="literal">login</tt> (from <tt class="literal">/etc/passwd</tt> file).</p>
</td></tr>
<tr><td><p><tt class="literal">IFS='</tt><em class="replaceable"><tt>chars</tt></em><tt class="literal">'</tt></p>
</td><td><p>
<a name="IXT-4-122734" />Input field separators; default is space, tab, and newline.</p>
</td></tr>
<tr><td><p><tt class="literal">LANG=</tt><em class="replaceable"><tt>dir</tt></em></p>
</td><td><p>Directory to use for certain language-dependent programs.
<a name="IXT-4-122735" /></p>
</td></tr>
<tr><td><p><tt class="literal">LC_ALL=</tt><em class="replaceable"><tt>locale</tt></em></p>
</td><td><p>(K93) Current locale; overrides LANG and the other LC_* variables.
<a name="IXT-4-122736" /></p>
</td></tr>
<tr><td><p><tt class="literal">LC_COLLATE=</tt><em class="replaceable"><tt>locale</tt></em></p>
</td><td><p>(K93) Locale to use for character collation (sorting order).
<a name="IXT-4-122737" /></p>
</td></tr>
<tr><td><p><tt class="literal">LC_CTYPE=</tt><em class="replaceable"><tt>locale</tt></em></p>
</td><td><p>(K93) Locale to use for character class functions.
(See the earlier <a href="ch04_02.htm#unut-ch-4-sect-2.2">Section 4.2.2</a>.)
<a name="IXT-4-122738" /></p>
</td></tr>