more.html

posix标准英文,html格式

</dd>
</dl>

<p>Repeat the previous search for <i>count</i>th line containing the last <i>pattern</i> (or not containing the last
<i>pattern</i>, if the previous search was <tt>"/!"</tt> or <tt>"?!"</tt> ).</p>

<h5><a name="tag_04_89_13_19"></a>Repeat Search in Reverse</h5>

<dl compact>
<dt><i>Synopsis</i>:</dt>

<dd>
<pre>
<b>[</b><i>count</i><b>]</b><tt>N
</tt>
</pre>
</dd>
</dl>

<p>Repeat the search in the opposite direction of the previous search for the <i>count</i>th line containing the last
<i>pattern</i> (or not containing the last <i>pattern</i>, if the previous search was <tt>"/!"</tt> or <tt>"?!"</tt> ).</p>

<h5><a name="tag_04_89_13_20"></a>Examine New File</h5>

<dl compact>
<dt><i>Synopsis</i>:</dt>

<dd>
<pre>
<tt>:e</tt> <b>[</b><i>filename</i><b>]</b><tt>&lt;newline&gt;
</tt>
</pre>
</dd>
</dl>

<p>Examine a new file. If the <i>filename</i> argument is not specified, the current file (see the <b>:n</b> and <b>:p</b> commands
below) shall be re-examined. The <i>filename</i> shall be subjected to the process of shell word expansions (see <a href=
"xcu_chap02.html#tag_02_06"><i>Word Expansions</i></a>); if more than a single pathname results, the effects are unspecified. If
<i>filename</i> is a number sign ( <tt>'#'</tt> ), the previously examined file shall be re-examined. If <i>filename</i> is not
accessible for any reason (including that it is a non-seekable file), an error message to this effect shall be displayed and the
current file and screen shall not change.</p>

<h5><a name="tag_04_89_13_21"></a>Examine Next File</h5>

<dl compact>
<dt><i>Synopsis</i>:</dt>

<dd>
<pre>
<b>[</b><i>count</i><b>]</b><tt>:n
</tt>
</pre>
</dd>
</dl>

<p>Examine the next file. If a number <i>count</i> is specified, the <i>count</i>th next file shall be examined. If <i>filename</i>
refers to a non-seekable file, the results are unspecified.</p>

<h5><a name="tag_04_89_13_22"></a>Examine Previous File</h5>

<dl compact>
<dt><i>Synopsis</i>:</dt>

<dd>
<pre>
<b>[</b><i>count</i><b>]</b><tt>:p
</tt>
</pre>
</dd>
</dl>

<p>Examine the previous file. If a number <i>count</i> is specified, the <i>count</i>th previous file shall be examined. If
<i>filename</i> refers to a non-seekable file, the results are unspecified.</p>

<h5><a name="tag_04_89_13_23"></a>Go to Tag</h5>

<dl compact>
<dt><i>Synopsis</i>:</dt>

<dd>
<pre>
<tt>:t</tt> <i>tagstring</i><tt>&lt;newline&gt;
</tt>
</pre>
</dd>
</dl>

<p>If the file containing the tag named by the <i>tagstring</i> argument is not the current file, examine the file, as if the
<b>:e</b> command was executed with that file as the argument. Otherwise, or in addition, display the screenful beginning with the
tag, as described for the <b>-t</b> option (see the OPTIONS section). If the <a href="../utilities/ctags.html"><i>ctags</i></a>
utility is not supported by the system, the use of <b>:t</b> produces undefined results.</p>

<h5><a name="tag_04_89_13_24"></a>Invoke Editor</h5>

<dl compact>
<dt><i>Synopsis</i>:</dt>

<dd>
<pre>
<tt>v
</tt>
</pre>
</dd>
</dl>

<p>Invoke an editor to edit the current file being examined. If standard input is being examined, the results are unspecified. The
name of the editor shall be taken from the environment variable <i>EDITOR ,</i> or shall default to <a href=
"../utilities/vi.html"><i>vi</i></a>. If the last pathname component in <i>EDITOR</i> is either <a href=
"../utilities/vi.html"><i>vi</i></a> or <a href="../utilities/ex.html"><i>ex</i></a>, the editor shall be invoked with a <b>-c</b>
<i>linenumber</i> command line argument, where <i>linenumber</i> is the line number of the file line containing the display line
currently displayed as the first line of the screen. It is implementation-defined whether line-setting options are passed to
editors other than <a href="../utilities/vi.html"><i>vi</i></a> and <a href="../utilities/ex.html"><i>ex</i></a>.</p>

<p>When the editor exits, <i>more</i> shall resume with the same file and screen as when the editor was invoked.</p>

<h5><a name="tag_04_89_13_25"></a>Display Position</h5>

<dl compact>
<dt><i>Synopsis</i>:</dt>

<dd>
<pre>
<tt>=
&lt;control&gt;-G
</tt>
</pre>
</dd>
</dl>

<p>Write a message for which the information references the first byte of the line after the last line of the file on the screen.
This message shall include the name of the file currently being examined, its number relative to the total number of files there
are to examine, the line number in the file, the byte number and the total bytes in the file, and what percentage of the file
precedes the current position. If <i>more</i> is reading from standard input, or the file is shorter than a single screen, the line
number, the byte number, the total bytes, and the percentage need not be written.</p>

<h5><a name="tag_04_89_13_26"></a>Quit</h5>

<dl compact>
<dt><i>Synopsis</i>:</dt>

<dd>
<pre>
<tt>q
:q
ZZ
</tt>
</pre>
</dd>
</dl>

<p>Exit <i>more</i>.</p>
</blockquote>

<h4><a name="tag_04_89_14"></a>EXIT STATUS</h4>

<blockquote>
<p>The following exit values shall be returned:</p>

<dl compact>
<dt>&nbsp;0</dt>

<dd>Successful completion.</dd>

<dt>&gt;0</dt>

<dd>An error occurred.</dd>
</dl>
</blockquote>

<h4><a name="tag_04_89_15"></a>CONSEQUENCES OF ERRORS</h4>

<blockquote>
<p>If an error is encountered accessing a file when using the <b>:n</b> command, <i>more</i> shall attempt to examine the next file
in the argument list, but the final exit status shall be affected. If an error is encountered accessing a file via the <b>:p</b>
command, <i>more</i> shall attempt to examine the previous file in the argument list, but the final exit status shall be affected.
If an error is encountered accessing a file via the <b>:e</b> command, <i>more</i> shall remain in the current file and the final
exit status shall not be affected.</p>
</blockquote>

<hr>
<div class="box"><em>The following sections are informative.</em></div>

<h4><a name="tag_04_89_16"></a>APPLICATION USAGE</h4>

<blockquote>
<p>When the standard output is not a terminal, only the <b>-s</b> filter-modification option is effective. This is based on
historical practice. For example, a typical implementation of <a href="../utilities/man.html"><i>man</i></a> pipes its output
through <i>more</i> <b>-s</b> to squeeze excess white space for terminal users. When <a href="../utilities/man.html"><i>man</i></a>
is piped to <a href="../utilities/lp.html"><i>lp</i></a>, however, it is undesirable for this squeezing to happen.</p>
</blockquote>

<h4><a name="tag_04_89_17"></a>EXAMPLES</h4>

<blockquote>
<p>The <b>-p</b> allows arbitrary commands to be executed at the start of each file. Examples are:</p>

<dl compact>
<dt><i>more&nbsp;</i> <b>-p&nbsp;G&nbsp;</b> <i>file1&nbsp;file2</i></dt>

<dd>
Examine each file starting with its last screenful.</dd>

<dt><i>more&nbsp;</i> <b>-p&nbsp;</b> 100&nbsp;<i>file1&nbsp;file2</i></dt>

<dd>
Examine each file starting with line 100 in the current position (usually the third line, so line 98 would be the first line
written).</dd>

<dt><i>more&nbsp;</i> <b>-p&nbsp;</b> /100&nbsp;<i>file1&nbsp;file2</i></dt>

<dd>
Examine each file starting with the first line containing the string <tt>"100"</tt> in the current position</dd>
</dl>
</blockquote>

<h4><a name="tag_04_89_18"></a>RATIONALE</h4>

<blockquote>
<p>The <i>more</i> utility, available in BSD and BSD-derived systems, was chosen as the prototype for the POSIX file display
program since it is more widely available than either the public-domain program <i>less</i> or than <i>pg</i>, a pager provided in
System V. The 4.4 BSD <i>more</i> is the model for the features selected; it is almost fully upwards-compatible from the 4.3 BSD
version in wide use and has become more amenable for <a href="../utilities/vi.html"><i>vi</i></a> users. Several features
originally derived from various file editors, found in both <i>less</i> and <i>pg</i>, have been added to this volume of
IEEE&nbsp;Std&nbsp;1003.1-2001 as they have proved extremely popular with users.</p>

<p>There are inconsistencies between <i>more</i> and <a href="../utilities/vi.html"><i>vi</i></a> that result from historical
practice. For example, the single-character commands <b>h</b>, <b>f</b>, <b>b</b>, and &lt;space&gt; are screen movers in
<i>more</i>, but cursor movers in <a href="../utilities/vi.html"><i>vi</i></a>. These inconsistencies were maintained because the
cursor movements are not applicable to <i>more</i> and the powerful functionality achieved without the use of the control key
justifies the differences.</p>

<p>The tags interface has been included in a program that is not a text editor because it promotes another degree of consistent
operation with <a href="../utilities/vi.html"><i>vi</i></a>. It is conceivable that the paging environment of <i>more</i> would be
superior for browsing source code files in some circumstances.</p>

<p>The operating mode referred to for block-mode terminals effectively adds a &lt;newline&gt; to each Synopsis line that currently
has none. So, for example, <b>d</b> &lt;newline&gt; would page one screenful. The mode could be triggered by a command line option,
environment variable, or some other method. The details are not imposed by this volume of IEEE&nbsp;Std&nbsp;1003.1-2001 because
there are so few systems known to support such terminals. Nevertheless, it was considered that all systems should be able to
support <i>more</i> given the exception cited for this small community of terminals because, in comparison to <a href=
"../utilities/vi.html"><i>vi</i></a>, the cursor movements are few and the command set relatively amenable to the optional
&lt;newline&gt;s.</p>

<p>Some versions of <i>more</i> provide a shell escaping mechanism similar to the <a href="../utilities/ex.html"><i>ex</i></a>
<b>!</b> command. The standard developers did not consider that this was necessary in a paginator, particularly given the wide
acceptance of multiple window terminals and job control features. (They chose to retain such features in the editors and <a href=
"../utilities/mailx.html"><i>mailx</i></a> because the shell interaction also gives an opportunity to modify the editing buffer,
which is not applicable to <i>more</i>.)</p>

<p>The <b>-p</b> (position) option replaces the <b>+</b> command because of the Utility Syntax Guidelines. In early proposals, it
took a <i>pattern</i> argument, but historical <i>less</i> provided the <i>more</i> general facility of a command. It would have
been desirable to use the same <b>-c</b> as <a href="../utilities/ex.html"><i>ex</i></a> and <a href=
"../utilities/vi.html"><i>vi</i></a>, but the letter was already in use.</p>

<p>The text stating &quot;from a non-rewindable stream ... implementations may limit the amount of backwards motion supported&quot; would
allow an implementation that permitted no backwards motion beyond text already on the screen. It was not possible to require a
minimum amount of backwards motion that would be effective for all conceivable device types. The implementation should allow the
user to back up as far as possible, within device and reasonable memory allocation constraints.</p>

<p>Historically, non-printable characters were displayed using the ARPA standard mappings, which are as follows:</p>

<ol>
<li>
<p>Printable characters are left alone.</p>
</li>

<li>
<p>Control characters less than \177 are represented as followed by the character offset from the <tt>'@'</tt> character in the
ASCII map; for example, \007 is represented as <tt>'G'</tt>.</p>
</li>

<li>
<p>\177 is represented as followed by <tt>'?'</tt>.</p>
</li>
</ol>

<p>The display of characters having their eighth bit set was less standard. Existing implementations use hex (0x00), octal (\000),
and a meta-bit display. (The latter displayed characters with their eighth bit set as the two characters <tt>"M-"</tt>, followed
by the seven-bit display as described previously.) The latter probably has the best claim to historical practice because it was
used with the <b>-v</b> option of 4 BSD and 4 BSD-derived versions of the <a href="../utilities/cat.html"><i>cat</i></a> utility
since 1980.</p>

<p>No specific display format is required by IEEE&nbsp;Std&nbsp;1003.1-2001. Implementations are encouraged to conform to historic
practice in the absence of any strong reason to diverge.</p>
</blockquote>

<h4><a name="tag_04_89_19"></a>FUTURE DIRECTIONS</h4>

<blockquote>
<p>None.</p>
</blockquote>

<h4><a name="tag_04_89_20"></a>SEE ALSO</h4>

<blockquote>
<p><a href="xcu_chap02.html#tag_02"><i>Shell Command Language</i></a>, <a href="ctags.html"><i>ctags</i></a>, <a href=
"ed.html"><i>ed</i></a>, <a href="ex.html"><i>ex</i></a>, <a href="vi.html"><i>vi</i></a></p>
</blockquote>

<h4><a name="tag_04_89_21"></a>CHANGE HISTORY</h4>

<blockquote>
<p>First released in Issue 4.</p>
</blockquote>

<h4><a name="tag_04_89_22"></a>Issue 5</h4>

<blockquote>
<p>The FUTURE DIRECTIONS section is added.</p>
</blockquote>

<h4><a name="tag_04_89_23"></a>Issue 6</h4>

<blockquote>
<p>This utility is marked as part of the User Portability Utilities option.</p>

<p>The obsolescent SYNOPSIS is removed.</p>

<p>The utility has been extensively reworked for alignment with the IEEE&nbsp;P1003.2b draft standard:</p>

<ul>
<li>
<p>Changes have been made as a result of IEEE PASC Interpretations 1003.2 #37 and #109.</p>
</li>

<li>
<p>The <i>more</i> utility should be able to handle underlined and emboldened displays of characters that are wider than a single
column position.</p>
</li>
</ul>
</blockquote>

<div class="box"><em>End of informative text.</em></div>

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