/usr/share/doc/diffutils-doc/Output-Formats.html

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<a name="Output-Formats"></a>
<div class="header">
<p>
Next: <a href="Incomplete-Lines.html#Incomplete-Lines" accesskey="n" rel="next">Incomplete Lines</a>, Previous: <a href="Comparison.html#Comparison" accesskey="p" rel="prev">Comparison</a>, Up: <a href="index.html#Top" accesskey="u" rel="up">Top</a> &nbsp; [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Index.html#Index" title="Index" rel="index">Index</a>]</p>
</div>
<a name="diff-Output-Formats"></a>
<h2 class="chapter">2 <code>diff</code> Output Formats</h2>
<a name="index-output-formats"></a>
<a name="index-format-of-diff-output"></a>

<p><code>diff</code> has several mutually exclusive options for output format.
The following sections describe each format, illustrating how
<code>diff</code> reports the differences between two sample input files.
</p>
<table class="menu" border="0" cellspacing="0">
<tr><td align="left" valign="top">&bull; <a href="#Sample-diff-Input" accesskey="1">Sample diff Input</a>:</td><td>&nbsp;&nbsp;</td><td align="left" valign="top">Sample <code>diff</code> input files for examples.
</td></tr>
<tr><td align="left" valign="top">&bull; <a href="#Context" accesskey="2">Context</a>:</td><td>&nbsp;&nbsp;</td><td align="left" valign="top">Showing differences with the surrounding text.
</td></tr>
<tr><td align="left" valign="top">&bull; <a href="#Side-by-Side" accesskey="3">Side by Side</a>:</td><td>&nbsp;&nbsp;</td><td align="left" valign="top">Showing differences in two columns.
</td></tr>
<tr><td align="left" valign="top">&bull; <a href="#Normal" accesskey="4">Normal</a>:</td><td>&nbsp;&nbsp;</td><td align="left" valign="top">Showing differences without surrounding text.
</td></tr>
<tr><td align="left" valign="top">&bull; <a href="#Scripts" accesskey="5">Scripts</a>:</td><td>&nbsp;&nbsp;</td><td align="left" valign="top">Generating scripts for other programs.
</td></tr>
<tr><td align="left" valign="top">&bull; <a href="#If_002dthen_002delse" accesskey="6">If-then-else</a>:</td><td>&nbsp;&nbsp;</td><td align="left" valign="top">Merging files with if-then-else.
</td></tr>
</table>

<hr>
<a name="Sample-diff-Input"></a>
<div class="header">
<p>
Next: <a href="#Context" accesskey="n" rel="next">Context</a>, Up: <a href="#Output-Formats" accesskey="u" rel="up">Output Formats</a> &nbsp; [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Index.html#Index" title="Index" rel="index">Index</a>]</p>
</div>
<a name="Two-Sample-Input-Files"></a>
<h3 class="section">2.1 Two Sample Input Files</h3>
<a name="index-diff-sample-input"></a>
<a name="index-sample-input-for-diff"></a>

<p>Here are two sample files that we will use in numerous examples to
illustrate the output of <code>diff</code> and how various options can change
it.
</p>
<p>This is the file <samp>lao</samp>:
</p>
<div class="example">
<pre class="example">The Way that can be told of is not the eternal Way;
The name that can be named is not the eternal name.
The Nameless is the origin of Heaven and Earth;
The Named is the mother of all things.
Therefore let there always be non-being,
  so we may see their subtlety,
And let there always be being,
  so we may see their outcome.
The two are the same,
But after they are produced,
  they have different names.
</pre></div>

<p>This is the file <samp>tzu</samp>:
</p>
<div class="example">
<pre class="example">The Nameless is the origin of Heaven and Earth;
The named is the mother of all things.

Therefore let there always be non-being,
  so we may see their subtlety,
And let there always be being,
  so we may see their outcome.
The two are the same,
But after they are produced,
  they have different names.
They both may be called deep and profound.
Deeper and more profound,
The door of all subtleties!
</pre></div>

<p>In this example, the first hunk contains just the first two lines of
<samp>lao</samp>, the second hunk contains the fourth line of <samp>lao</samp>
opposing the second and third lines of <samp>tzu</samp>, and the last hunk
contains just the last three lines of <samp>tzu</samp>.
</p>
<hr>
<a name="Context"></a>
<div class="header">
<p>
Next: <a href="#Side-by-Side" accesskey="n" rel="next">Side by Side</a>, Previous: <a href="#Sample-diff-Input" accesskey="p" rel="prev">Sample diff Input</a>, Up: <a href="#Output-Formats" accesskey="u" rel="up">Output Formats</a> &nbsp; [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Index.html#Index" title="Index" rel="index">Index</a>]</p>
</div>
<a name="Showing-Differences-in-Their-Context"></a>
<h3 class="section">2.2 Showing Differences in Their Context</h3>
<a name="index-context-output-format"></a>
<a name="index-_0021-output-format"></a>

<p>Usually, when you are looking at the differences between files, you will
also want to see the parts of the files near the lines that differ, to
help you understand exactly what has changed.  These nearby parts of the
files are called the <em>context</em>.
</p>
<p><acronym>GNU</acronym> <code>diff</code> provides two output formats that show context
around the differing lines: <em>context format</em> and <em>unified
format</em>.  It can optionally show in which function or section of the
file the differing lines are found.
</p>
<p>If you are distributing new versions of files to other people in the
form of <code>diff</code> output, you should use one of the output formats
that show context so that they can apply the diffs even if they have
made small changes of their own to the files.  <code>patch</code> can apply
the diffs in this case by searching in the files for the lines of
context around the differing lines; if those lines are actually a few
lines away from where the diff says they are, <code>patch</code> can adjust
the line numbers accordingly and still apply the diff correctly.
See <a href="Merging-with-patch.html#Imperfect">Imperfect</a>, for more information on using <code>patch</code> to apply
imperfect diffs.
</p>
<table class="menu" border="0" cellspacing="0">
<tr><td align="left" valign="top">&bull; <a href="#Context-Format" accesskey="1">Context Format</a>:</td><td>&nbsp;&nbsp;</td><td align="left" valign="top">An output format that shows surrounding lines.
</td></tr>
<tr><td align="left" valign="top">&bull; <a href="#Unified-Format" accesskey="2">Unified Format</a>:</td><td>&nbsp;&nbsp;</td><td align="left" valign="top">A more compact output format that shows context.
</td></tr>
<tr><td align="left" valign="top">&bull; <a href="#Sections" accesskey="3">Sections</a>:</td><td>&nbsp;&nbsp;</td><td align="left" valign="top">Showing which sections of the files differences are in.
</td></tr>
<tr><td align="left" valign="top">&bull; <a href="#Alternate-Names" accesskey="4">Alternate Names</a>:</td><td>&nbsp;&nbsp;</td><td align="left" valign="top">Showing alternate file names in context headers.
</td></tr>
</table>

<hr>
<a name="Context-Format"></a>
<div class="header">
<p>
Next: <a href="#Unified-Format" accesskey="n" rel="next">Unified Format</a>, Up: <a href="#Context" accesskey="u" rel="up">Context</a> &nbsp; [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Index.html#Index" title="Index" rel="index">Index</a>]</p>
</div>
<a name="Context-Format-1"></a>
<h4 class="subsection">2.2.1 Context Format</h4>

<p>The context output format shows several lines of context around the
lines that differ.  It is the standard format for distributing updates
to source code.
</p>
<p>To select this output format, use the
<samp>--context<span class="roman">[</span>=<var>lines</var><span class="roman">]</span></samp> (<samp>-C <var>lines</var></samp>)
or <samp>-c</samp> option.  The
argument <var>lines</var> that some of these options take is the number of
lines of context to show.  If you do not specify <var>lines</var>, it
defaults to three.  For proper operation, <code>patch</code> typically needs
at least two lines of context.
</p>
<table class="menu" border="0" cellspacing="0">
<tr><td align="left" valign="top">&bull; <a href="#Example-Context" accesskey="1">Example Context</a>:</td><td>&nbsp;&nbsp;</td><td align="left" valign="top">Sample output in context format.
</td></tr>
<tr><td align="left" valign="top">&bull; <a href="#Less-Context" accesskey="2">Less Context</a>:</td><td>&nbsp;&nbsp;</td><td align="left" valign="top">Another sample with less context.
</td></tr>
<tr><td align="left" valign="top">&bull; <a href="#Detailed-Context" accesskey="3">Detailed Context</a>:</td><td>&nbsp;&nbsp;</td><td align="left" valign="top">A detailed description of the context output format.
</td></tr>
</table>

<hr>
<a name="Example-Context"></a>
<div class="header">
<p>
Next: <a href="#Less-Context" accesskey="n" rel="next">Less Context</a>, Up: <a href="#Context-Format" accesskey="u" rel="up">Context Format</a> &nbsp; [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Index.html#Index" title="Index" rel="index">Index</a>]</p>
</div>
<a name="An-Example-of-Context-Format"></a>
<h4 class="subsubsection">2.2.1.1 An Example of Context Format</h4>

<p>Here is the output of &lsquo;<samp>diff -c lao tzu</samp>&rsquo; (see <a href="#Sample-diff-Input">Sample diff Input</a>,
for the complete contents of the two files).  Notice that up to three
lines that are not different are shown around each line that is
different; they are the context lines.  Also notice that the first two
hunks have run together, because their contents overlap.
</p>
<div class="example">
<pre class="example">*** lao	2002-02-21 23:30:39.942229878 -0800
--- tzu	2002-02-21 23:30:50.442260588 -0800
***************
*** 1,7 ****
- The Way that can be told of is not the eternal Way;
- The name that can be named is not the eternal name.
  The Nameless is the origin of Heaven and Earth;
! The Named is the mother of all things.
  Therefore let there always be non-being,
    so we may see their subtlety,
  And let there always be being,
--- 1,6 ----
  The Nameless is the origin of Heaven and Earth;
! The named is the mother of all things.
! 
  Therefore let there always be non-being,
    so we may see their subtlety,
  And let there always be being,
***************
*** 9,11 ****
--- 8,13 ----
  The two are the same,
  But after they are produced,
    they have different names.
+ They both may be called deep and profound.
+ Deeper and more profound,
+ The door of all subtleties!
</pre></div>

<hr>
<a name="Less-Context"></a>
<div class="header">
<p>
Next: <a href="#Detailed-Context" accesskey="n" rel="next">Detailed Context</a>, Previous: <a href="#Example-Context" accesskey="p" rel="prev">Example Context</a>, Up: <a href="#Context-Format" accesskey="u" rel="up">Context Format</a> &nbsp; [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Index.html#Index" title="Index" rel="index">Index</a>]</p>
</div>
<a name="An-Example-of-Context-Format-with-Less-Context"></a>
<h4 class="subsubsection">2.2.1.2 An Example of Context Format with Less Context</h4>

<p>Here is the output of &lsquo;<samp>diff -C 1 lao tzu</samp>&rsquo; (see <a href="#Sample-diff-Input">Sample diff Input</a>, for the complete contents of the two files).  Notice that at
most one context line is reported here.
</p>
<div class="example">
<pre class="example">*** lao	2002-02-21 23:30:39.942229878 -0800
--- tzu	2002-02-21 23:30:50.442260588 -0800
***************
*** 1,5 ****
- The Way that can be told of is not the eternal Way;
- The name that can be named is not the eternal name.
  The Nameless is the origin of Heaven and Earth;
! The Named is the mother of all things.
  Therefore let there always be non-being,
--- 1,4 ----
  The Nameless is the origin of Heaven and Earth;
! The named is the mother of all things.
! 
  Therefore let there always be non-being,
***************
*** 11 ****
--- 10,13 ----
    they have different names.
+ They both may be called deep and profound.
+ Deeper and more profound,
+ The door of all subtleties!
</pre></div>

<hr>
<a name="Detailed-Context"></a>
<div class="header">
<p>
Previous: <a href="#Less-Context" accesskey="p" rel="prev">Less Context</a>, Up: <a href="#Context-Format" accesskey="u" rel="up">Context Format</a> &nbsp; [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Index.html#Index" title="Index" rel="index">Index</a>]</p>
</div>
<a name="Detailed-Description-of-Context-Format"></a>
<h4 class="subsubsection">2.2.1.3 Detailed Description of Context Format</h4>

<p>The context output format starts with a two-line header, which looks
like this:
</p>
<div class="example">
<pre class="example">*** <var>from-file</var> <var>from-file-modification-time</var>
--- <var>to-file</var> <var>to-file-modification time</var>
</pre></div>

<p><a name="index-LC_005fTIME"></a>
<a name="index-time-stamp-format_002c-context-diffs"></a>
The time stamp normally looks like &lsquo;<samp>2002-02-21 23:30:39.942229878
-0800</samp>&rsquo; to indicate the date, time with fractional seconds, and time
zone in <a href="ftp://ftp.isi.edu/in-notes/rfc2822.txt">Internet RFC
2822 format</a>.  (The fractional seconds are omitted on hosts that do
not support fractional time stamps.)  However, a traditional time
stamp like &lsquo;<samp>Thu Feb 21 23:30:39 2002</samp>&rsquo; is used if the
<code>LC_TIME</code> locale category is either &lsquo;<samp>C</samp>&rsquo; or &lsquo;<samp>POSIX</samp>&rsquo;.
</p>
<p>You can change the header&rsquo;s content with the
<samp>--label=<var>label</var></samp> option; see <a href="#Alternate-Names">Alternate Names</a>.
</p>
<p>Next come one or more hunks of differences; each hunk shows one area
where the files differ.  Context format hunks look like this:
</p>
<div class="example">
<pre class="example">***************
*** <var>from-file-line-numbers</var> ****
  <var>from-file-line</var>
  <var>from-file-line</var>&hellip;
--- <var>to-file-line-numbers</var> ----
  <var>to-file-line</var>
  <var>to-file-line</var>&hellip;
</pre></div>

<p>If a hunk contains two or more lines, its line numbers look like
&lsquo;<samp><var>start</var>,<var>end</var></samp>&rsquo;.  Otherwise only its end line number
appears.  An empty hunk is considered to end at the line that precedes
the hunk.
</p>
<p>The lines of context around the lines that differ start with two space
characters.  The lines that differ between the two files start with one
of the following indicator characters, followed by a space character:
</p>
<dl compact="compact">
<dt>&lsquo;<samp>!</samp>&rsquo;</dt>
<dd><p>A line that is part of a group of one or more lines that changed between
the two files.  There is a corresponding group of lines marked with
&lsquo;<samp>!</samp>&rsquo; in the part of this hunk for the other file.
</p>
</dd>
<dt>&lsquo;<samp>+</samp>&rsquo;</dt>
<dd><p>An &ldquo;inserted&rdquo; line in the second file that corresponds to nothing in
the first file.
</p>
</dd>
<dt>&lsquo;<samp>-</samp>&rsquo;</dt>
<dd><p>A &ldquo;deleted&rdquo; line in the first file that corresponds to nothing in the
second file.
</p></dd>
</dl>

<p>If all of the changes in a hunk are insertions, the lines of
<var>from-file</var> are omitted.  If all of the changes are deletions, the
lines of <var>to-file</var> are omitted.
</p>
<hr>
<a name="Unified-Format"></a>
<div class="header">
<p>
Next: <a href="#Sections" accesskey="n" rel="next">Sections</a>, Previous: <a href="#Context-Format" accesskey="p" rel="prev">Context Format</a>, Up: <a href="#Context" accesskey="u" rel="up">Context</a> &nbsp; [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Index.html#Index" title="Index" rel="index">Index</a>]</p>
</div>
<a name="Unified-Format-1"></a>
<h4 class="subsection">2.2.2 Unified Format</h4>
<a name="index-unified-output-format"></a>
<a name="index-_002b_002d-output-format"></a>

<p>The unified output format is a variation on the context format that is
more compact because it omits redundant context lines.  To select this
output format, use the
<samp>--unified<span class="roman">[</span>=<var>lines</var><span class="roman">]</span></samp> (<samp>-U <var>lines</var></samp>),
or <samp>-u</samp> option.
The argument <var>lines</var> is the number of lines of context to show.
When it is not given, it defaults to three.
</p>
<p>At present, only <acronym>GNU</acronym> <code>diff</code> can produce this format and
only <acronym>GNU</acronym> <code>patch</code> can automatically apply diffs in this
format.  For proper operation, <code>patch</code> typically needs at
least three lines of context.
</p>
<table class="menu" border="0" cellspacing="0">
<tr><td align="left" valign="top">&bull; <a href="#Example-Unified" accesskey="1">Example Unified</a>:</td><td>&nbsp;&nbsp;</td><td align="left" valign="top">Sample output in unified format.
</td></tr>
<tr><td align="left" valign="top">&bull; <a href="#Detailed-Unified" accesskey="2">Detailed Unified</a>:</td><td>&nbsp;&nbsp;</td><td align="left" valign="top">A detailed description of unified format.
</td></tr>
</table>

<hr>
<a name="Example-Unified"></a>
<div class="header">
<p>
Next: <a href="#Detailed-Unified" accesskey="n" rel="next">Detailed Unified</a>, Up: <a href="#Unified-Format" accesskey="u" rel="up">Unified Format</a> &nbsp; [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Index.html#Index" title="Index" rel="index">Index</a>]</p>
</div>
<a name="An-Example-of-Unified-Format"></a>
<h4 class="subsubsection">2.2.2.1 An Example of Unified Format</h4>

<p>Here is the output of the command &lsquo;<samp>diff -u lao tzu</samp>&rsquo;
(see <a href="#Sample-diff-Input">Sample diff Input</a>, for the complete contents of the two files):
</p>
<div class="example">
<pre class="example">--- lao	2002-02-21 23:30:39.942229878 -0800
+++ tzu	2002-02-21 23:30:50.442260588 -0800
@@ -1,7 +1,6 @@
-The Way that can be told of is not the eternal Way;
-The name that can be named is not the eternal name.
 The Nameless is the origin of Heaven and Earth;
-The Named is the mother of all things.
+The named is the mother of all things.
+
 Therefore let there always be non-being,
   so we may see their subtlety,
 And let there always be being,
@@ -9,3 +8,6 @@
 The two are the same,
 But after they are produced,
   they have different names.
+They both may be called deep and profound.
+Deeper and more profound,
+The door of all subtleties!
</pre></div>

<hr>
<a name="Detailed-Unified"></a>
<div class="header">
<p>
Previous: <a href="#Example-Unified" accesskey="p" rel="prev">Example Unified</a>, Up: <a href="#Unified-Format" accesskey="u" rel="up">Unified Format</a> &nbsp; [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Index.html#Index" title="Index" rel="index">Index</a>]</p>
</div>
<a name="Detailed-Description-of-Unified-Format"></a>
<h4 class="subsubsection">2.2.2.2 Detailed Description of Unified Format</h4>

<p>The unified output format starts with a two-line header, which looks
like this:
</p>
<div class="example">
<pre class="example">--- <var>from-file</var> <var>from-file-modification-time</var>
+++ <var>to-file</var> <var>to-file-modification-time</var>
</pre></div>

<p><a name="index-time-stamp-format_002c-unified-diffs"></a>
The time stamp looks like &lsquo;<samp>2002-02-21 23:30:39.942229878 -0800</samp>&rsquo;
to indicate the date, time with fractional seconds, and time zone.
The fractional seconds are omitted on hosts that do not support
fractional time stamps.
</p>
<p>You can change the header&rsquo;s content with the
<samp>--label=<var>label</var></samp> option. See <a href="#Alternate-Names">Alternate Names</a>.
</p>
<p>Next come one or more hunks of differences; each hunk shows one area
where the files differ.  Unified format hunks look like this:
</p>
<div class="example">
<pre class="example">@@ <var>from-file-line-numbers</var> <var>to-file-line-numbers</var> @@
 <var>line-from-either-file</var>
 <var>line-from-either-file</var>&hellip;
</pre></div>

<p>If a hunk contains just one line, only its start line number appears.
Otherwise its line numbers look like &lsquo;<samp><var>start</var>,<var>count</var></samp>&rsquo;.
An empty hunk is considered to start at the line that follows the hunk.
</p>
<p>If a hunk and its context contain two or more lines, its
line numbers look like &lsquo;<samp><var>start</var>,<var>count</var></samp>&rsquo;.  Otherwise only
its end line number appears.  An empty hunk is considered to end at
the line that precedes the hunk.
</p>
<p>The lines common to both files begin with a space character.  The lines
that actually differ between the two files have one of the following
indicator characters in the left print column:
</p>
<dl compact="compact">
<dt>&lsquo;<samp>+</samp>&rsquo;</dt>
<dd><p>A line was added here to the first file.
</p>
</dd>
<dt>&lsquo;<samp>-</samp>&rsquo;</dt>
<dd><p>A line was removed here from the first file.
</p></dd>
</dl>

<hr>
<a name="Sections"></a>
<div class="header">
<p>
Next: <a href="#Alternate-Names" accesskey="n" rel="next">Alternate Names</a>, Previous: <a href="#Unified-Format" accesskey="p" rel="prev">Unified Format</a>, Up: <a href="#Context" accesskey="u" rel="up">Context</a> &nbsp; [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Index.html#Index" title="Index" rel="index">Index</a>]</p>
</div>
<a name="Showing-Which-Sections-Differences-Are-in"></a>
<h4 class="subsection">2.2.3 Showing Which Sections Differences Are in</h4>
<a name="index-headings"></a>
<a name="index-section-headings"></a>

<p>Sometimes you might want to know which part of the files each change
falls in.  If the files are source code, this could mean which
function was changed.  If the files are documents, it could mean which
chapter or appendix was changed.  <acronym>GNU</acronym> <code>diff</code> can
show this by displaying the nearest section heading line that precedes
the differing lines.  Which lines are &ldquo;section headings&rdquo; is
determined by a regular expression.
</p>
<table class="menu" border="0" cellspacing="0">
<tr><td align="left" valign="top">&bull; <a href="#Specified-Headings" accesskey="1">Specified Headings</a>:</td><td>&nbsp;&nbsp;</td><td align="left" valign="top">Showing headings that match regular expressions.
</td></tr>
<tr><td align="left" valign="top">&bull; <a href="#C-Function-Headings" accesskey="2">C Function Headings</a>:</td><td>&nbsp;&nbsp;</td><td align="left" valign="top">Showing headings of C functions.
</td></tr>
</table>

<hr>
<a name="Specified-Headings"></a>
<div class="header">
<p>
Next: <a href="#C-Function-Headings" accesskey="n" rel="next">C Function Headings</a>, Up: <a href="#Sections" accesskey="u" rel="up">Sections</a> &nbsp; [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Index.html#Index" title="Index" rel="index">Index</a>]</p>
</div>
<a name="Showing-Lines-That-Match-Regular-Expressions"></a>
<h4 class="subsubsection">2.2.3.1 Showing Lines That Match Regular Expressions</h4>
<a name="index-specified-headings"></a>
<a name="index-regular-expression-matching-headings"></a>

<p>To show in which sections differences occur for files that are not
source code for C or similar languages, use the
<samp>--show-function-line=<var>regexp</var></samp> (<samp>-F <var>regexp</var></samp>) option.
<code>diff</code>
considers lines that match the <code>grep</code>-style regular expression
<var>regexp</var> to be the beginning
of a section of the file.  Here are suggested regular expressions for
some common languages:
</p>
<dl compact="compact">
<dt>&lsquo;<samp>^[[:alpha:]$_]</samp>&rsquo;</dt>
<dd><p>C, C++, Prolog
</p></dd>
<dt>&lsquo;<samp>^(</samp>&rsquo;</dt>
<dd><p>Lisp
</p></dd>
<dt>&lsquo;<samp>^@node</samp>&rsquo;</dt>
<dd><p>Texinfo
</p></dd>
</dl>

<p>This option does not automatically select an output format; in order to
use it, you must select the context format (see <a href="#Context-Format">Context Format</a>) or
unified format (see <a href="#Unified-Format">Unified Format</a>).  In other output formats it
has no effect.
</p>
<p>The <samp>--show-function-line</samp> (<samp>-F</samp>) option finds the nearest
unchanged line that precedes each hunk of differences and matches the
given regular expression.  Then it adds that line to the end of the
line of asterisks in the context format, or to the &lsquo;<samp>@@</samp>&rsquo; line in
unified format.  If no matching line exists, this option leaves the output for
that hunk unchanged.  If that line is more than 40 characters long, it
outputs only the first 40 characters.  You can specify more than one
regular expression for such lines; <code>diff</code> tries to match each line
against each regular expression, starting with the last one given.  This
means that you can use <samp>-p</samp> and <samp>-F</samp> together, if you wish.
</p>
<hr>
<a name="C-Function-Headings"></a>
<div class="header">
<p>
Previous: <a href="#Specified-Headings" accesskey="p" rel="prev">Specified Headings</a>, Up: <a href="#Sections" accesskey="u" rel="up">Sections</a> &nbsp; [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Index.html#Index" title="Index" rel="index">Index</a>]</p>
</div>
<a name="Showing-C-Function-Headings"></a>
<h4 class="subsubsection">2.2.3.2 Showing C Function Headings</h4>
<a name="index-C-function-headings"></a>
<a name="index-function-headings_002c-C"></a>

<p>To show in which functions differences occur for C and similar
languages, you can use the <samp>--show-c-function</samp> (<samp>-p</samp>) option.
This option automatically defaults to the context output format
(see <a href="#Context-Format">Context Format</a>), with the default number of lines of context.
You can override that number with <samp>-C <var>lines</var></samp> elsewhere in the
command line.  You can override both the format and the number with
<samp>-U <var>lines</var></samp> elsewhere in the command line.
</p>
<p>The <samp>--show-c-function</samp> (<samp>-p</samp>) option is equivalent to
<samp>-F '^[[:alpha:]$_]'</samp> if the unified format is specified, otherwise
<samp>-c -F '^[[:alpha:]$_]'</samp> (see <a href="#Specified-Headings">Specified Headings</a>).  <acronym>GNU</acronym>
<code>diff</code> provides this option for the sake of convenience.
</p>
<hr>
<a name="Alternate-Names"></a>
<div class="header">
<p>
Previous: <a href="#Sections" accesskey="p" rel="prev">Sections</a>, Up: <a href="#Context" accesskey="u" rel="up">Context</a> &nbsp; [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Index.html#Index" title="Index" rel="index">Index</a>]</p>
</div>
<a name="Showing-Alternate-File-Names"></a>
<h4 class="subsection">2.2.4 Showing Alternate File Names</h4>
<a name="index-alternate-file-names"></a>
<a name="index-file-name-alternates"></a>

<p>If you are comparing two files that have meaningless or uninformative
names, you might want <code>diff</code> to show alternate names in the header
of the context and unified output formats.  To do this, use the
<samp>--label=<var>label</var></samp> option.  The first time
you give this option, its argument replaces the name and date of the
first file in the header; the second time, its argument replaces the
name and date of the second file.  If you give this option more than
twice, <code>diff</code> reports an error.  The <samp>--label</samp> option does not
affect the file names in the <code>pr</code> header when the <samp>-l</samp> or
<samp>--paginate</samp> option is used (see <a href="Adjusting-Output.html#Pagination">Pagination</a>).
</p>
<p>Here are the first two lines of the output from &lsquo;<samp>diff -C 2
--label=original --label=modified lao tzu</samp>&rsquo;:
</p>
<div class="example">
<pre class="example">*** original
--- modified
</pre></div>

<hr>
<a name="Side-by-Side"></a>
<div class="header">
<p>
Next: <a href="#Normal" accesskey="n" rel="next">Normal</a>, Previous: <a href="#Context" accesskey="p" rel="prev">Context</a>, Up: <a href="#Output-Formats" accesskey="u" rel="up">Output Formats</a> &nbsp; [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Index.html#Index" title="Index" rel="index">Index</a>]</p>
</div>
<a name="Showing-Differences-Side-by-Side"></a>
<h3 class="section">2.3 Showing Differences Side by Side</h3>
<a name="index-side-by-side"></a>
<a name="index-two_002dcolumn-output"></a>
<a name="index-columnar-output"></a>

<p><code>diff</code> can produce a side by side difference listing of two files.
The files are listed in two columns with a gutter between them.  The
gutter contains one of the following markers:
</p>
<dl compact="compact">
<dt>white space</dt>
<dd><p>The corresponding lines are in common.  That is, either the lines are
identical, or the difference is ignored because of one of the
<samp>--ignore</samp> options (see <a href="Comparison.html#White-Space">White Space</a>).
</p>
</dd>
<dt>&lsquo;<samp>|</samp>&rsquo;</dt>
<dd><p>The corresponding lines differ, and they are either both complete
or both incomplete.
</p>
</dd>
<dt>&lsquo;<samp>&lt;</samp>&rsquo;</dt>
<dd><p>The files differ and only the first file contains the line.
</p>
</dd>
<dt>&lsquo;<samp>&gt;</samp>&rsquo;</dt>
<dd><p>The files differ and only the second file contains the line.
</p>
</dd>
<dt>&lsquo;<samp>(</samp>&rsquo;</dt>
<dd><p>Only the first file contains the line, but the difference is ignored.
</p>
</dd>
<dt>&lsquo;<samp>)</samp>&rsquo;</dt>
<dd><p>Only the second file contains the line, but the difference is ignored.
</p>
</dd>
<dt>&lsquo;<samp>\</samp>&rsquo;</dt>
<dd><p>The corresponding lines differ, and only the first line is incomplete.
</p>
</dd>
<dt>&lsquo;<samp>/</samp>&rsquo;</dt>
<dd><p>The corresponding lines differ, and only the second line is incomplete.
</p></dd>
</dl>

<p>Normally, an output line is incomplete if and only if the lines that it
contains are incomplete.  See <a href="Incomplete-Lines.html#Incomplete-Lines">Incomplete Lines</a>.  However, when an
output line represents two differing lines, one might be incomplete
while the other is not.  In this case, the output line is complete,
but its the gutter is marked &lsquo;<samp>\</samp>&rsquo; if the first line is incomplete,
&lsquo;<samp>/</samp>&rsquo; if the second line is.
</p>
<p>Side by side format is sometimes easiest to read, but it has limitations.
It generates much wider output than usual, and truncates lines that are
too long to fit.  Also, it relies on lining up output more heavily than
usual, so its output looks particularly bad if you use varying
width fonts, nonstandard tab stops, or nonprinting characters.
</p>
<p>You can use the <code>sdiff</code> command to interactively merge side by side
differences.  See <a href="Interactive-Merging.html#Interactive-Merging">Interactive Merging</a>, for more information on merging files.
</p>
<table class="menu" border="0" cellspacing="0">
<tr><td align="left" valign="top">&bull; <a href="#Side-by-Side-Format" accesskey="1">Side by Side Format</a>:</td><td>&nbsp;&nbsp;</td><td align="left" valign="top">Controlling side by side output format.
</td></tr>
<tr><td align="left" valign="top">&bull; <a href="#Example-Side-by-Side" accesskey="2">Example Side by Side</a>:</td><td>&nbsp;&nbsp;</td><td align="left" valign="top">Sample side by side output.
</td></tr>
</table>

<hr>
<a name="Side-by-Side-Format"></a>
<div class="header">
<p>
Next: <a href="#Example-Side-by-Side" accesskey="n" rel="next">Example Side by Side</a>, Up: <a href="#Side-by-Side" accesskey="u" rel="up">Side by Side</a> &nbsp; [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Index.html#Index" title="Index" rel="index">Index</a>]</p>
</div>
<a name="Controlling-Side-by-Side-Format"></a>
<h4 class="subsection">2.3.1 Controlling Side by Side Format</h4>
<a name="index-side-by-side-format"></a>

<p>The <samp>--side-by-side</samp> (<samp>-y</samp>) option selects side by side
format.  Because side by side output lines contain two input lines, the
output is wider than usual: normally 130 print columns, which can fit
onto a traditional printer line.  You can set the width of the output
with the <samp>--width=<var>columns</var></samp> (<samp>-W <var>columns</var></samp>)
option.  The output is split into two halves of equal width, separated by a
small gutter to mark differences; the right half is aligned to a tab
stop so that tabs line up.  Input lines that are too long to fit in half
of an output line are truncated for output.
</p>
<p>The <samp>--left-column</samp> option prints only the left column of two
common lines.  The <samp>--suppress-common-lines</samp> option suppresses
common lines entirely.
</p>
<hr>
<a name="Example-Side-by-Side"></a>
<div class="header">
<p>
Previous: <a href="#Side-by-Side-Format" accesskey="p" rel="prev">Side by Side Format</a>, Up: <a href="#Side-by-Side" accesskey="u" rel="up">Side by Side</a> &nbsp; [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Index.html#Index" title="Index" rel="index">Index</a>]</p>
</div>
<a name="An-Example-of-Side-by-Side-Format"></a>
<h4 class="subsection">2.3.2 An Example of Side by Side Format</h4>

<p>Here is the output of the command &lsquo;<samp>diff -y -W 72 lao tzu</samp>&rsquo;
(see <a href="#Sample-diff-Input">Sample diff Input</a>, for the complete contents of the two files).
</p>
<div class="example">
<pre class="example">The Way that can be told of is n   &lt;
The name that can be named is no   &lt;
The Nameless is the origin of He        The Nameless is the origin of He
The Named is the mother of all t   |    The named is the mother of all t
                                   &gt;
Therefore let there always be no        Therefore let there always be no
  so we may see their subtlety,           so we may see their subtlety,
And let there always be being,          And let there always be being,
  so we may see their outcome.            so we may see their outcome.
The two are the same,                   The two are the same,
But after they are produced,            But after they are produced,
  they have different names.              they have different names.
                                   &gt;    They both may be called deep and
                                   &gt;    Deeper and more profound,
                                   &gt;    The door of all subtleties!
</pre></div>

<hr>
<a name="Normal"></a>
<div class="header">
<p>
Next: <a href="#Scripts" accesskey="n" rel="next">Scripts</a>, Previous: <a href="#Side-by-Side" accesskey="p" rel="prev">Side by Side</a>, Up: <a href="#Output-Formats" accesskey="u" rel="up">Output Formats</a> &nbsp; [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Index.html#Index" title="Index" rel="index">Index</a>]</p>
</div>
<a name="Showing-Differences-Without-Context"></a>
<h3 class="section">2.4 Showing Differences Without Context</h3>
<a name="index-normal-output-format"></a>
<a name="index-_003c-output-format"></a>

<p>The &ldquo;normal&rdquo; <code>diff</code> output format shows each hunk of differences
without any surrounding context.  Sometimes such output is the clearest
way to see how lines have changed, without the clutter of nearby
unchanged lines (although you can get similar results with the context
or unified formats by using 0 lines of context).  However, this format
is no longer widely used for sending out patches; for that purpose, the
context format (see <a href="#Context-Format">Context Format</a>) and the unified format
(see <a href="#Unified-Format">Unified Format</a>) are superior.  Normal format is the default for
compatibility with older versions of <code>diff</code> and the <acronym>POSIX</acronym>
standard.  Use the <samp>--normal</samp> option to select this output
format explicitly.
</p>
<table class="menu" border="0" cellspacing="0">
<tr><td align="left" valign="top">&bull; <a href="#Example-Normal" accesskey="1">Example Normal</a>:</td><td>&nbsp;&nbsp;</td><td align="left" valign="top">Sample output in the normal format.
</td></tr>
<tr><td align="left" valign="top">&bull; <a href="#Detailed-Normal" accesskey="2">Detailed Normal</a>:</td><td>&nbsp;&nbsp;</td><td align="left" valign="top">A detailed description of normal output format.
</td></tr>
</table>

<hr>
<a name="Example-Normal"></a>
<div class="header">
<p>
Next: <a href="#Detailed-Normal" accesskey="n" rel="next">Detailed Normal</a>, Up: <a href="#Normal" accesskey="u" rel="up">Normal</a> &nbsp; [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Index.html#Index" title="Index" rel="index">Index</a>]</p>
</div>
<a name="An-Example-of-Normal-Format"></a>
<h4 class="subsection">2.4.1 An Example of Normal Format</h4>

<p>Here is the output of the command &lsquo;<samp>diff lao tzu</samp>&rsquo;
(see <a href="#Sample-diff-Input">Sample diff Input</a>, for the complete contents of the two files).
Notice that it shows only the lines that are different between the two
files.
</p>
<div class="example">
<pre class="example">1,2d0
&lt; The Way that can be told of is not the eternal Way;
&lt; The name that can be named is not the eternal name.
4c2,3
&lt; The Named is the mother of all things.
---
&gt; The named is the mother of all things.
&gt; 
11a11,13
&gt; They both may be called deep and profound.
&gt; Deeper and more profound,
&gt; The door of all subtleties!
</pre></div>

<hr>
<a name="Detailed-Normal"></a>
<div class="header">
<p>
Previous: <a href="#Example-Normal" accesskey="p" rel="prev">Example Normal</a>, Up: <a href="#Normal" accesskey="u" rel="up">Normal</a> &nbsp; [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Index.html#Index" title="Index" rel="index">Index</a>]</p>
</div>
<a name="Detailed-Description-of-Normal-Format"></a>
<h4 class="subsection">2.4.2 Detailed Description of Normal Format</h4>

<p>The normal output format consists of one or more hunks of differences;
each hunk shows one area where the files differ.  Normal format hunks
look like this:
</p>
<div class="example">
<pre class="example"><var>change-command</var>
&lt; <var>from-file-line</var>
&lt; <var>from-file-line</var>&hellip;
---
&gt; <var>to-file-line</var>
&gt; <var>to-file-line</var>&hellip;
</pre></div>

<p>There are three types of change commands.  Each consists of a line
number or comma-separated range of lines in the first file, a single
character indicating the kind of change to make, and a line number or
comma-separated range of lines in the second file.  All line numbers are
the original line numbers in each file.  The types of change commands
are:
</p>
<dl compact="compact">
<dt>&lsquo;<samp><var>l</var>a<var>r</var></samp>&rsquo;</dt>
<dd><p>Add the lines in range <var>r</var> of the second file after line <var>l</var> of
the first file.  For example, &lsquo;<samp>8a12,15</samp>&rsquo; means append lines 12&ndash;15
of file 2 after line 8 of file 1; or, if changing file 2 into file 1,
delete lines 12&ndash;15 of file 2.
</p>
</dd>
<dt>&lsquo;<samp><var>f</var>c<var>t</var></samp>&rsquo;</dt>
<dd><p>Replace the lines in range <var>f</var> of the first file with lines in range
<var>t</var> of the second file.  This is like a combined add and delete, but
more compact.  For example, &lsquo;<samp>5,7c8,10</samp>&rsquo; means change lines 5&ndash;7 of
file 1 to read as lines 8&ndash;10 of file 2; or, if changing file 2 into
file 1, change lines 8&ndash;10 of file 2 to read as lines 5&ndash;7 of file 1.
</p>
</dd>
<dt>&lsquo;<samp><var>r</var>d<var>l</var></samp>&rsquo;</dt>
<dd><p>Delete the lines in range <var>r</var> from the first file; line <var>l</var> is where
they would have appeared in the second file had they not been deleted.
For example, &lsquo;<samp>5,7d3</samp>&rsquo; means delete lines 5&ndash;7 of file 1; or, if
changing file 2 into file 1, append lines 5&ndash;7 of file 1 after line 3 of
file 2.
</p></dd>
</dl>

<hr>
<a name="Scripts"></a>
<div class="header">
<p>
Next: <a href="#If_002dthen_002delse" accesskey="n" rel="next">If-then-else</a>, Previous: <a href="#Normal" accesskey="p" rel="prev">Normal</a>, Up: <a href="#Output-Formats" accesskey="u" rel="up">Output Formats</a> &nbsp; [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Index.html#Index" title="Index" rel="index">Index</a>]</p>
</div>
<a name="Making-Edit-Scripts"></a>
<h3 class="section">2.5 Making Edit Scripts</h3>
<a name="index-script-output-formats"></a>

<p>Several output modes produce command scripts for editing <var>from-file</var>
to produce <var>to-file</var>.
</p>
<table class="menu" border="0" cellspacing="0">
<tr><td align="left" valign="top">&bull; <a href="#ed-Scripts" accesskey="1">ed Scripts</a>:</td><td>&nbsp;&nbsp;</td><td align="left" valign="top">Using <code>diff</code> to produce commands for <code>ed</code>.
</td></tr>
<tr><td align="left" valign="top">&bull; <a href="#Forward-ed" accesskey="2">Forward ed</a>:</td><td>&nbsp;&nbsp;</td><td align="left" valign="top">Making forward <code>ed</code> scripts.
</td></tr>
<tr><td align="left" valign="top">&bull; <a href="#RCS" accesskey="3">RCS</a>:</td><td>&nbsp;&nbsp;</td><td align="left" valign="top">A special <code>diff</code> output format used by <acronym>RCS</acronym>.
</td></tr>
</table>

<hr>
<a name="ed-Scripts"></a>
<div class="header">
<p>
Next: <a href="#Forward-ed" accesskey="n" rel="next">Forward ed</a>, Up: <a href="#Scripts" accesskey="u" rel="up">Scripts</a> &nbsp; [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Index.html#Index" title="Index" rel="index">Index</a>]</p>
</div>
<a name="ed-Scripts-1"></a>
<h4 class="subsection">2.5.1 <code>ed</code> Scripts</h4>
<a name="index-ed-script-output-format"></a>

<p><code>diff</code> can produce commands that direct the <code>ed</code> text editor
to change the first file into the second file.  Long ago, this was the
only output mode that was suitable for editing one file into another
automatically; today, with <code>patch</code>, it is almost obsolete.  Use the
<samp>--ed</samp> (<samp>-e</samp>) option to select this output format.
</p>
<p>Like the normal format (see <a href="#Normal">Normal</a>), this output format does not
show any context; unlike the normal format, it does not include the
information necessary to apply the diff in reverse (to produce the first
file if all you have is the second file and the diff).
</p>
<p>If the file <samp>d</samp> contains the output of &lsquo;<samp>diff -e old new</samp>&rsquo;, then
the command &lsquo;<samp>(cat d &amp;&amp; echo w) | ed - old</samp>&rsquo; edits <samp>old</samp> to make
it a copy of <samp>new</samp>.  More generally, if <samp>d1</samp>, <samp>d2</samp>,
&hellip;, <samp>dN</samp> contain the outputs of &lsquo;<samp>diff -e old new1</samp>&rsquo;,
&lsquo;<samp>diff -e new1 new2</samp>&rsquo;, &hellip;, &lsquo;<samp>diff -e newN-1 newN</samp>&rsquo;,
respectively, then the command &lsquo;<samp>(cat d1 d2 &hellip; dN &amp;&amp; echo w) |
ed - old</samp>&rsquo; edits <samp>old</samp> to make it a copy of <samp>newN</samp>.
</p>
<table class="menu" border="0" cellspacing="0">
<tr><td align="left" valign="top">&bull; <a href="#Example-ed" accesskey="1">Example ed</a>:</td><td>&nbsp;&nbsp;</td><td align="left" valign="top">A sample <code>ed</code> script.
</td></tr>
<tr><td align="left" valign="top">&bull; <a href="#Detailed-ed" accesskey="2">Detailed ed</a>:</td><td>&nbsp;&nbsp;</td><td align="left" valign="top">A detailed description of <code>ed</code> format.
</td></tr>
</table>

<hr>
<a name="Example-ed"></a>
<div class="header">
<p>
Next: <a href="#Detailed-ed" accesskey="n" rel="next">Detailed ed</a>, Up: <a href="#ed-Scripts" accesskey="u" rel="up">ed Scripts</a> &nbsp; [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Index.html#Index" title="Index" rel="index">Index</a>]</p>
</div>
<a name="Example-ed-Script"></a>
<h4 class="subsubsection">2.5.1.1 Example <code>ed</code> Script</h4>

<p>Here is the output of &lsquo;<samp>diff -e lao tzu</samp>&rsquo; (see <a href="#Sample-diff-Input">Sample diff Input</a>, for the complete contents of the two files):
</p>
<div class="example">
<pre class="example">11a
They both may be called deep and profound.
Deeper and more profound,
The door of all subtleties!
.
4c
The named is the mother of all things.

.
1,2d
</pre></div>

<hr>
<a name="Detailed-ed"></a>
<div class="header">
<p>
Previous: <a href="#Example-ed" accesskey="p" rel="prev">Example ed</a>, Up: <a href="#ed-Scripts" accesskey="u" rel="up">ed Scripts</a> &nbsp; [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Index.html#Index" title="Index" rel="index">Index</a>]</p>
</div>
<a name="Detailed-Description-of-ed-Format"></a>
<h4 class="subsubsection">2.5.1.2 Detailed Description of <code>ed</code> Format</h4>

<p>The <code>ed</code> output format consists of one or more hunks of
differences.  The changes closest to the ends of the files come first so
that commands that change the number of lines do not affect how
<code>ed</code> interprets line numbers in succeeding commands.  <code>ed</code>
format hunks look like this:
</p>
<div class="example">
<pre class="example"><var>change-command</var>
<var>to-file-line</var>
<var>to-file-line</var>&hellip;
.
</pre></div>

<p>Because <code>ed</code> uses a single period on a line to indicate the
end of input, <acronym>GNU</acronym> <code>diff</code> protects lines of changes
that contain a single period on a line by writing two periods instead,
then writing a subsequent <code>ed</code> command to change the two
periods into one.  The <code>ed</code> format cannot represent an
incomplete line, so if the second file ends in a changed incomplete
line, <code>diff</code> reports an error and then pretends that a newline
was appended.
</p>
<p>There are three types of change commands.  Each consists of a line
number or comma-separated range of lines in the first file and a single
character indicating the kind of change to make.  All line numbers are
the original line numbers in the file.  The types of change commands
are:
</p>
<dl compact="compact">
<dt>&lsquo;<samp><var>l</var>a</samp>&rsquo;</dt>
<dd><p>Add text from the second file after line <var>l</var> in the first file.  For
example, &lsquo;<samp>8a</samp>&rsquo; means to add the following lines after line 8 of file
1.
</p>
</dd>
<dt>&lsquo;<samp><var>r</var>c</samp>&rsquo;</dt>
<dd><p>Replace the lines in range <var>r</var> in the first file with the following
lines.  Like a combined add and delete, but more compact.  For example,
&lsquo;<samp>5,7c</samp>&rsquo; means change lines 5&ndash;7 of file 1 to read as the text file
2.
</p>
</dd>
<dt>&lsquo;<samp><var>r</var>d</samp>&rsquo;</dt>
<dd><p>Delete the lines in range <var>r</var> from the first file.  For example,
&lsquo;<samp>5,7d</samp>&rsquo; means delete lines 5&ndash;7 of file 1.
</p></dd>
</dl>

<hr>
<a name="Forward-ed"></a>
<div class="header">
<p>
Next: <a href="#RCS" accesskey="n" rel="next">RCS</a>, Previous: <a href="#ed-Scripts" accesskey="p" rel="prev">ed Scripts</a>, Up: <a href="#Scripts" accesskey="u" rel="up">Scripts</a> &nbsp; [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Index.html#Index" title="Index" rel="index">Index</a>]</p>
</div>
<a name="Forward-ed-Scripts"></a>
<h4 class="subsection">2.5.2 Forward <code>ed</code> Scripts</h4>
<a name="index-forward-ed-script-output-format"></a>

<p><code>diff</code> can produce output that is like an <code>ed</code> script, but
with hunks in forward (front to back) order.  The format of the commands
is also changed slightly: command characters precede the lines they
modify, spaces separate line numbers in ranges, and no attempt is made
to disambiguate hunk lines consisting of a single period.  Like
<code>ed</code> format, forward <code>ed</code> format cannot represent incomplete
lines.
</p>
<p>Forward <code>ed</code> format is not very useful, because neither <code>ed</code>
nor <code>patch</code> can apply diffs in this format.  It exists mainly for
compatibility with older versions of <code>diff</code>.  Use the <samp>-f</samp> or
<samp>--forward-ed</samp> option to select it.
</p>
<hr>
<a name="RCS"></a>
<div class="header">
<p>
Previous: <a href="#Forward-ed" accesskey="p" rel="prev">Forward ed</a>, Up: <a href="#Scripts" accesskey="u" rel="up">Scripts</a> &nbsp; [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Index.html#Index" title="Index" rel="index">Index</a>]</p>
</div>
<a name="RCS-Scripts"></a>
<h4 class="subsection">2.5.3 <acronym>RCS</acronym> Scripts</h4>
<a name="index-RCS-script-output-format"></a>

<p>The <acronym>RCS</acronym> output format is designed specifically for use by
the Revision Control System, which is a set of free programs used for
organizing different versions and systems of files.  Use the
<samp>--rcs</samp> (<samp>-n</samp>) option to select this output format.  It
is like the forward <code>ed</code> format (see <a href="#Forward-ed">Forward ed</a>), but it
can represent arbitrary changes to the contents of a file because it
avoids the forward <code>ed</code> format&rsquo;s problems with lines
consisting of a single period and with incomplete lines.  Instead of
ending text sections with a line consisting of a single period, each
command specifies the number of lines it affects; a combination of the
&lsquo;<samp>a</samp>&rsquo; and &lsquo;<samp>d</samp>&rsquo; commands are used instead of &lsquo;<samp>c</samp>&rsquo;.  Also, if
the second file ends in a changed incomplete line, then the output
also ends in an incomplete line.
</p>
<p>Here is the output of &lsquo;<samp>diff -n lao tzu</samp>&rsquo; (see <a href="#Sample-diff-Input">Sample diff Input</a>, for the complete contents of the two files):
</p>
<div class="example">
<pre class="example">d1 2
d4 1
a4 2
The named is the mother of all things.

a11 3
They both may be called deep and profound.
Deeper and more profound,
The door of all subtleties!
</pre></div>

<hr>
<a name="If_002dthen_002delse"></a>
<div class="header">
<p>
Previous: <a href="#Scripts" accesskey="p" rel="prev">Scripts</a>, Up: <a href="#Output-Formats" accesskey="u" rel="up">Output Formats</a> &nbsp; [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Index.html#Index" title="Index" rel="index">Index</a>]</p>
</div>
<a name="Merging-Files-with-If_002dthen_002delse"></a>
<h3 class="section">2.6 Merging Files with If-then-else</h3>
<a name="index-merged-output-format"></a>
<a name="index-if_002dthen_002delse-output-format"></a>
<a name="index-C-if_002dthen_002delse-output-format"></a>
<a name="index-ifdef-output-format"></a>

<p>You can use <code>diff</code> to merge two files of C source code.  The output
of <code>diff</code> in this format contains all the lines of both files.
Lines common to both files are output just once; the differing parts are
separated by the C preprocessor directives <code>#ifdef <var>name</var></code> or
<code>#ifndef <var>name</var></code>, <code>#else</code>, and <code>#endif</code>.  When
compiling the output, you select which version to use by either defining
or leaving undefined the macro <var>name</var>.
</p>
<p>To merge two files, use <code>diff</code> with the <samp>-D <var>name</var></samp> or
<samp>--ifdef=<var>name</var></samp> option.  The argument <var>name</var> is the C
preprocessor identifier to use in the <code>#ifdef</code> and <code>#ifndef</code>
directives.
</p>
<p>For example, if you change an instance of <code>wait (&amp;s)</code> to
<code>waitpid (-1, &amp;s, 0)</code> and then merge the old and new files with
the <samp>--ifdef=HAVE_WAITPID</samp> option, then the affected part of your code
might look like this:
</p>
<div class="example">
<pre class="example">    do {
#ifndef HAVE_WAITPID
        if ((w = wait (&amp;s)) &lt; 0  &amp;&amp;  errno != EINTR)
#else /* HAVE_WAITPID */
        if ((w = waitpid (-1, &amp;s, 0)) &lt; 0  &amp;&amp;  errno != EINTR)
#endif /* HAVE_WAITPID */
            return w;
    } while (w != child);
</pre></div>

<p>You can specify formats for languages other than C by using line group
formats and line formats, as described in the next sections.
</p>
<table class="menu" border="0" cellspacing="0">
<tr><td align="left" valign="top">&bull; <a href="#Line-Group-Formats" accesskey="1">Line Group Formats</a>:</td><td>&nbsp;&nbsp;</td><td align="left" valign="top">Formats for general if-then-else line groups.
</td></tr>
<tr><td align="left" valign="top">&bull; <a href="#Line-Formats" accesskey="2">Line Formats</a>:</td><td>&nbsp;&nbsp;</td><td align="left" valign="top">Formats for each line in a line group.
</td></tr>
<tr><td align="left" valign="top">&bull; <a href="#Example-If_002dthen_002delse" accesskey="3">Example If-then-else</a>:</td><td>&nbsp;&nbsp;</td><td align="left" valign="top">Sample if-then-else format output.
</td></tr>
<tr><td align="left" valign="top">&bull; <a href="#Detailed-If_002dthen_002delse" accesskey="4">Detailed If-then-else</a>:</td><td>&nbsp;&nbsp;</td><td align="left" valign="top">A detailed description of if-then-else format.
</td></tr>
</table>

<hr>
<a name="Line-Group-Formats"></a>
<div class="header">
<p>
Next: <a href="#Line-Formats" accesskey="n" rel="next">Line Formats</a>, Up: <a href="#If_002dthen_002delse" accesskey="u" rel="up">If-then-else</a> &nbsp; [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Index.html#Index" title="Index" rel="index">Index</a>]</p>
</div>
<a name="Line-Group-Formats-1"></a>
<h4 class="subsection">2.6.1 Line Group Formats</h4>
<a name="index-line-group-formats"></a>
<a name="index-formats-for-if_002dthen_002delse-line-groups"></a>

<p>Line group formats let you specify formats suitable for many
applications that allow if-then-else input, including programming
languages and text formatting languages.  A line group format specifies
the output format for a contiguous group of similar lines.
</p>
<p>For example, the following command compares the TeX files <samp>old</samp>
and <samp>new</samp>, and outputs a merged file in which old regions are
surrounded by &lsquo;<samp>\begin{em}</samp>&rsquo;-&lsquo;<samp>\end{em}</samp>&rsquo; lines, and new
regions are surrounded by &lsquo;<samp>\begin{bf}</samp>&rsquo;-&lsquo;<samp>\end{bf}</samp>&rsquo; lines.
</p>
<div class="example">
<pre class="example">diff \
   --old-group-format='\begin{em}
%&lt;\end{em}
' \
   --new-group-format='\begin{bf}
%&gt;\end{bf}
' \
   old new
</pre></div>

<p>The following command is equivalent to the above example, but it is a
little more verbose, because it spells out the default line group formats.
</p>
<div class="example">
<pre class="example">diff \
   --old-group-format='\begin{em}
%&lt;\end{em}
' \
   --new-group-format='\begin{bf}
%&gt;\end{bf}
' \
   --unchanged-group-format='%=' \
   --changed-group-format='\begin{em}
%&lt;\end{em}
\begin{bf}
%&gt;\end{bf}
' \
   old new
</pre></div>

<p>Here is a more advanced example, which outputs a diff listing with
headers containing line numbers in a &ldquo;plain English&rdquo; style.
</p>
<div class="example">
<pre class="example">diff \
   --unchanged-group-format='' \
   --old-group-format='-------- %dn line%(n=1?:s) deleted at %df:
%&lt;' \
   --new-group-format='-------- %dN line%(N=1?:s) added after %de:
%&gt;' \
   --changed-group-format='-------- %dn line%(n=1?:s) changed at %df:
%&lt;-------- to:
%&gt;' \
   old new
</pre></div>

<p>To specify a line group format, use <code>diff</code> with one of the options
listed below.  You can specify up to four line group formats, one for
each kind of line group.  You should quote <var>format</var>, because it
typically contains shell metacharacters.
</p>
<dl compact="compact">
<dt><samp>--old-group-format=<var>format</var></samp></dt>
<dd><p>These line groups are hunks containing only lines from the first file.
The default old group format is the same as the changed group format if
it is specified; otherwise it is a format that outputs the line group as-is.
</p>
</dd>
<dt><samp>--new-group-format=<var>format</var></samp></dt>
<dd><p>These line groups are hunks containing only lines from the second
file.  The default new group format is same as the changed group
format if it is specified; otherwise it is a format that outputs the
line group as-is.
</p>
</dd>
<dt><samp>--changed-group-format=<var>format</var></samp></dt>
<dd><p>These line groups are hunks containing lines from both files.  The
default changed group format is the concatenation of the old and new
group formats.
</p>
</dd>
<dt><samp>--unchanged-group-format=<var>format</var></samp></dt>
<dd><p>These line groups contain lines common to both files.  The default
unchanged group format is a format that outputs the line group as-is.
</p></dd>
</dl>

<p>In a line group format, ordinary characters represent themselves;
conversion specifications start with &lsquo;<samp>%</samp>&rsquo; and have one of the
following forms.
</p>
<dl compact="compact">
<dt>&lsquo;<samp>%&lt;</samp>&rsquo;</dt>
<dd><p>stands for the lines from the first file, including the trailing newline.
Each line is formatted according to the old line format (see <a href="#Line-Formats">Line Formats</a>).
</p>
</dd>
<dt>&lsquo;<samp>%&gt;</samp>&rsquo;</dt>
<dd><p>stands for the lines from the second file, including the trailing newline.
Each line is formatted according to the new line format.
</p>
</dd>
<dt>&lsquo;<samp>%=</samp>&rsquo;</dt>
<dd><p>stands for the lines common to both files, including the trailing newline.
Each line is formatted according to the unchanged line format.
</p>
</dd>
<dt>&lsquo;<samp>%%</samp>&rsquo;</dt>
<dd><p>stands for &lsquo;<samp>%</samp>&rsquo;.
</p>
</dd>
<dt>&lsquo;<samp>%c'<var>C</var>'</samp>&rsquo;</dt>
<dd><p>where <var>C</var> is a single character, stands for <var>C</var>.
<var>C</var> may not be a backslash or an apostrophe.
For example, &lsquo;<samp>%c':'</samp>&rsquo; stands for a colon, even inside
the then-part of an if-then-else format, which a colon would
normally terminate.
</p>
</dd>
<dt>&lsquo;<samp>%c'\<var>O</var>'</samp>&rsquo;</dt>
<dd><p>where <var>O</var> is a string of 1, 2, or 3 octal digits,
stands for the character with octal code <var>O</var>.
For example, &lsquo;<samp>%c'\0'</samp>&rsquo; stands for a null character.
</p>
</dd>
<dt>&lsquo;<samp><var>F</var><var>n</var></samp>&rsquo;</dt>
<dd><p>where <var>F</var> is a <code>printf</code> conversion specification and <var>n</var> is one
of the following letters, stands for <var>n</var>&rsquo;s value formatted with <var>F</var>.
</p>
<dl compact="compact">
<dt>&lsquo;<samp>e</samp>&rsquo;</dt>
<dd><p>The line number of the line just before the group in the old file.
</p>
</dd>
<dt>&lsquo;<samp>f</samp>&rsquo;</dt>
<dd><p>The line number of the first line in the group in the old file;
equals <var>e</var> + 1.
</p>
</dd>
<dt>&lsquo;<samp>l</samp>&rsquo;</dt>
<dd><p>The line number of the last line in the group in the old file.
</p>
</dd>
<dt>&lsquo;<samp>m</samp>&rsquo;</dt>
<dd><p>The line number of the line just after the group in the old file;
equals <var>l</var> + 1.
</p>
</dd>
<dt>&lsquo;<samp>n</samp>&rsquo;</dt>
<dd><p>The number of lines in the group in the old file; equals <var>l</var> - <var>f</var> + 1.
</p>
</dd>
<dt>&lsquo;<samp>E, F, L, M, N</samp>&rsquo;</dt>
<dd><p>Likewise, for lines in the new file.
</p>
</dd>
</dl>

<a name="index-LC_005fNUMERIC"></a>
<p>The <code>printf</code> conversion specification can be &lsquo;<samp>%d</samp>&rsquo;,
&lsquo;<samp>%o</samp>&rsquo;, &lsquo;<samp>%x</samp>&rsquo;, or &lsquo;<samp>%X</samp>&rsquo;, specifying decimal, octal,
lower case hexadecimal, or upper case hexadecimal output
respectively.  After the &lsquo;<samp>%</samp>&rsquo; the following options can appear in
sequence: a series of zero or more flags; an integer
specifying the minimum field width; and a period followed by an
optional integer specifying the minimum number of digits.
The flags are &lsquo;<samp>-</samp>&rsquo; for left-justification, &lsquo;<samp>'</samp>&rsquo; for separating
the digit into groups as specified by the <code>LC_NUMERIC</code> locale category,
and &lsquo;<samp>0</samp>&rsquo; for padding with zeros instead of spaces.
For example, &lsquo;<samp>%5dN</samp>&rsquo; prints the number of new lines in the group
in a field of width 5 characters, using the <code>printf</code> format <code>&quot;%5d&quot;</code>.
</p>
</dd>
<dt>&lsquo;<samp>(<var>A</var>=<var>B</var>?<var>T</var>:<var>E</var>)</samp>&rsquo;</dt>
<dd><p>If <var>A</var> equals <var>B</var> then <var>T</var> else <var>E</var>.
<var>A</var> and <var>B</var> are each either a decimal constant
or a single letter interpreted as above.
This format spec is equivalent to <var>T</var> if
<var>A</var>&rsquo;s value equals <var>B</var>&rsquo;s; otherwise it is equivalent to <var>E</var>.
</p>
<p>For example, &lsquo;<samp>%(N=0?no:%dN) line%(N=1?:s)</samp>&rsquo; is equivalent to
&lsquo;<samp>no lines</samp>&rsquo; if <var>N</var> (the number of lines in the group in the
new file) is 0, to &lsquo;<samp>1 line</samp>&rsquo; if <var>N</var> is 1, and to &lsquo;<samp>%dN lines</samp>&rsquo;
otherwise.
</p></dd>
</dl>

<hr>
<a name="Line-Formats"></a>
<div class="header">
<p>
Next: <a href="#Example-If_002dthen_002delse" accesskey="n" rel="next">Example If-then-else</a>, Previous: <a href="#Line-Group-Formats" accesskey="p" rel="prev">Line Group Formats</a>, Up: <a href="#If_002dthen_002delse" accesskey="u" rel="up">If-then-else</a> &nbsp; [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Index.html#Index" title="Index" rel="index">Index</a>]</p>
</div>
<a name="Line-Formats-1"></a>
<h4 class="subsection">2.6.2 Line Formats</h4>
<a name="index-line-formats"></a>

<p>Line formats control how each line taken from an input file is
output as part of a line group in if-then-else format.
</p>
<p>For example, the following command outputs text with a one-character
change indicator to the left of the text.  The first character of output
is &lsquo;<samp>-</samp>&rsquo; for deleted lines, &lsquo;<samp>|</samp>&rsquo; for added lines, and a space for
unchanged lines.  The formats contain newline characters where newlines
are desired on output.
</p>
<div class="example">
<pre class="example">diff \
   --old-line-format='-%l
' \
   --new-line-format='|%l
' \
   --unchanged-line-format=' %l
' \
   old new
</pre></div>

<p>To specify a line format, use one of the following options.  You should
quote <var>format</var>, since it often contains shell metacharacters.
</p>
<dl compact="compact">
<dt><samp>--old-line-format=<var>format</var></samp></dt>
<dd><p>formats lines just from the first file.
</p>
</dd>
<dt><samp>--new-line-format=<var>format</var></samp></dt>
<dd><p>formats lines just from the second file.
</p>
</dd>
<dt><samp>--unchanged-line-format=<var>format</var></samp></dt>
<dd><p>formats lines common to both files.
</p>
</dd>
<dt><samp>--line-format=<var>format</var></samp></dt>
<dd><p>formats all lines; in effect, it sets all three above options simultaneously.
</p></dd>
</dl>

<p>In a line format, ordinary characters represent themselves;
conversion specifications start with &lsquo;<samp>%</samp>&rsquo; and have one of the
following forms.
</p>
<dl compact="compact">
<dt>&lsquo;<samp>%l</samp>&rsquo;</dt>
<dd><p>stands for the contents of the line, not counting its trailing
newline (if any).  This format ignores whether the line is incomplete;
See <a href="Incomplete-Lines.html#Incomplete-Lines">Incomplete Lines</a>.
</p>
</dd>
<dt>&lsquo;<samp>%L</samp>&rsquo;</dt>
<dd><p>stands for the contents of the line, including its trailing newline
(if any).  If a line is incomplete, this format preserves its
incompleteness.
</p>
</dd>
<dt>&lsquo;<samp>%%</samp>&rsquo;</dt>
<dd><p>stands for &lsquo;<samp>%</samp>&rsquo;.
</p>
</dd>
<dt>&lsquo;<samp>%c'<var>C</var>'</samp>&rsquo;</dt>
<dd><p>where <var>C</var> is a single character, stands for <var>C</var>.
<var>C</var> may not be a backslash or an apostrophe.
For example, &lsquo;<samp>%c':'</samp>&rsquo; stands for a colon.
</p>
</dd>
<dt>&lsquo;<samp>%c'\<var>O</var>'</samp>&rsquo;</dt>
<dd><p>where <var>O</var> is a string of 1, 2, or 3 octal digits,
stands for the character with octal code <var>O</var>.
For example, &lsquo;<samp>%c'\0'</samp>&rsquo; stands for a null character.
</p>
</dd>
<dt>&lsquo;<samp><var>F</var>n</samp>&rsquo;</dt>
<dd><p>where <var>F</var> is a <code>printf</code> conversion specification,
stands for the line number formatted with <var>F</var>.
For example, &lsquo;<samp>%.5dn</samp>&rsquo; prints the line number using the
<code>printf</code> format <code>&quot;%.5d&quot;</code>.  See <a href="#Line-Group-Formats">Line Group Formats</a>, for
more about printf conversion specifications.
</p>
</dd>
</dl>

<p>The default line format is &lsquo;<samp>%l</samp>&rsquo; followed by a newline character.
</p>
<p>If the input contains tab characters and it is important that they line
up on output, you should ensure that &lsquo;<samp>%l</samp>&rsquo; or &lsquo;<samp>%L</samp>&rsquo; in a line
format is just after a tab stop (e.g. by preceding &lsquo;<samp>%l</samp>&rsquo; or
&lsquo;<samp>%L</samp>&rsquo; with a tab character), or you should use the <samp>-t</samp> or
<samp>--expand-tabs</samp> option.
</p>
<p>Taken together, the line and line group formats let you specify many
different formats.  For example, the following command uses a format
similar to normal <code>diff</code> format.  You can tailor this command
to get fine control over <code>diff</code> output.
</p>
<div class="example">
<pre class="example">diff \
   --old-line-format='&lt; %l
' \
   --new-line-format='&gt; %l
' \
   --old-group-format='%df%(f=l?:,%dl)d%dE
%&lt;' \
   --new-group-format='%dea%dF%(F=L?:,%dL)
%&gt;' \
   --changed-group-format='%df%(f=l?:,%dl)c%dF%(F=L?:,%dL)
%&lt;---
%&gt;' \
   --unchanged-group-format='' \
   old new
</pre></div>

<hr>
<a name="Example-If_002dthen_002delse"></a>
<div class="header">
<p>
Next: <a href="#Detailed-If_002dthen_002delse" accesskey="n" rel="next">Detailed If-then-else</a>, Previous: <a href="#Line-Formats" accesskey="p" rel="prev">Line Formats</a>, Up: <a href="#If_002dthen_002delse" accesskey="u" rel="up">If-then-else</a> &nbsp; [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Index.html#Index" title="Index" rel="index">Index</a>]</p>
</div>
<a name="An-Example-of-If_002dthen_002delse-Format"></a>
<h4 class="subsection">2.6.3 An Example of If-then-else Format</h4>

<p>Here is the output of &lsquo;<samp>diff -DTWO lao tzu</samp>&rsquo; (see <a href="#Sample-diff-Input">Sample diff Input</a>, for the complete contents of the two files):
</p>
<div class="example">
<pre class="example">#ifndef TWO
The Way that can be told of is not the eternal Way;
The name that can be named is not the eternal name.
#endif /* ! TWO */
The Nameless is the origin of Heaven and Earth;
#ifndef TWO
The Named is the mother of all things.
#else /* TWO */
The named is the mother of all things.

#endif /* TWO */
Therefore let there always be non-being,
  so we may see their subtlety,
And let there always be being,
  so we may see their outcome.
The two are the same,
But after they are produced,
  they have different names.
#ifdef TWO
They both may be called deep and profound.
Deeper and more profound,
The door of all subtleties!
#endif /* TWO */
</pre></div>

<hr>
<a name="Detailed-If_002dthen_002delse"></a>
<div class="header">
<p>
Previous: <a href="#Example-If_002dthen_002delse" accesskey="p" rel="prev">Example If-then-else</a>, Up: <a href="#If_002dthen_002delse" accesskey="u" rel="up">If-then-else</a> &nbsp; [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Index.html#Index" title="Index" rel="index">Index</a>]</p>
</div>
<a name="Detailed-Description-of-If_002dthen_002delse-Format"></a>
<h4 class="subsection">2.6.4 Detailed Description of If-then-else Format</h4>

<p>For lines common to both files, <code>diff</code> uses the unchanged line
group format.  For each hunk of differences in the merged output
format, if the hunk contains only lines from the first file,
<code>diff</code> uses the old line group format; if the hunk contains only
lines from the second file, <code>diff</code> uses the new group format;
otherwise, <code>diff</code> uses the changed group format.
</p>
<p>The old, new, and unchanged line formats specify the output format of
lines from the first file, lines from the second file, and lines common
to both files, respectively.
</p>
<p>The option <samp>--ifdef=<var>name</var></samp> is equivalent to
the following sequence of options using shell syntax:
</p>
<div class="example">
<pre class="example">--old-group-format='#ifndef <var>name</var>
%&lt;#endif /* ! <var>name</var> */
' \
--new-group-format='#ifdef <var>name</var>
%&gt;#endif /* <var>name</var> */
' \
--unchanged-group-format='%=' \
--changed-group-format='#ifndef <var>name</var>
%&lt;#else /* <var>name</var> */
%&gt;#endif /* <var>name</var> */
'
</pre></div>

<p>You should carefully check the <code>diff</code> output for proper nesting.
For example, when using the <samp>-D <var>name</var></samp> or
<samp>--ifdef=<var>name</var></samp> option, you should check that if the
differing lines contain any of the C preprocessor directives
&lsquo;<samp>#ifdef</samp>&rsquo;, &lsquo;<samp>#ifndef</samp>&rsquo;, &lsquo;<samp>#else</samp>&rsquo;, &lsquo;<samp>#elif</samp>&rsquo;, or
&lsquo;<samp>#endif</samp>&rsquo;, they are nested properly and match.  If they don&rsquo;t, you
must make corrections manually.  It is a good idea to carefully check
the resulting code anyway to make sure that it really does what you
want it to; depending on how the input files were produced, the output
might contain duplicate or otherwise incorrect code.
</p>
<p>The <code>patch</code> <samp>-D <var>name</var></samp> option behaves like
the <code>diff</code> <samp>-D <var>name</var></samp> option, except it operates on
a file and a diff to produce a merged file.  See <a href="Invoking-patch.html#patch-Options">patch Options</a>.
</p>
<hr>
<div class="header">
<p>
Previous: <a href="#Example-If_002dthen_002delse" accesskey="p" rel="prev">Example If-then-else</a>, Up: <a href="#If_002dthen_002delse" accesskey="u" rel="up">If-then-else</a> &nbsp; [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Index.html#Index" title="Index" rel="index">Index</a>]</p>
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