From 28f631e02bbf7e4cbd763fc74c4941d3f55a030f Mon Sep 17 00:00:00 2001
From: johannst <johannst@users.noreply.github.com>
Date: Sat, 19 Sep 2020 13:57:06 +0000
Subject: deploy: 4a5cd61b7c536ecf1bdb288cb6d584c190b1f6c7

---
 tools/bash.html | 40 ++++++++++++++++++++++++++++++++++++++--
 1 file changed, 38 insertions(+), 2 deletions(-)

(limited to 'tools')

diff --git a/tools/bash.html b/tools/bash.html
index 7d74cc9..f7278b6 100644
--- a/tools/bash.html
+++ b/tools/bash.html
@@ -233,6 +233,42 @@ command 2&gt;&amp;1 &gt;file
 <li>duplicate <code>fd 1</code> to <code>fd 2</code>, effectively redirecting <code>stderr</code> to <code>stdout</code></li>
 <li>redirect <code>stdout</code> to <code>file</code></li>
 </ol>
+<h2><a class="header" href="#argument-parsing-with-getopts" id="argument-parsing-with-getopts">Argument parsing with <code>getopts</code></a></h2>
+<p>The <code>getopts</code> builtin uses following global variables:</p>
+<ul>
+<li><code>OPTARG</code>, value of last option argument</li>
+<li><code>OPTIND</code>, index of the next argument to process (user must reset)</li>
+<li><code>OPTERR</code>, display errors if set to <code>1</code> </li>
+</ul>
+<pre><code class="language-bash">getopts &lt;optstring&gt; &lt;param&gt; [&lt;args&gt;]
+</code></pre>
+<ul>
+<li><code>&lt;optstring&gt;</code> specifies the names of supported options, eg <code>f:c</code>
+<ul>
+<li><code>f:</code> means <code>-f</code> option with an argument</li>
+<li><code>c</code> means <code>-c</code> option without an argument</li>
+</ul>
+</li>
+<li><code>&lt;param&gt;</code> specifies a variable name which <code>getopts</code> fills with the last parsed option argument</li>
+<li><code>&lt;args&gt;</code> optionally specify argument string to parse, by default <code>getopts</code> parses <code>$@</code></li>
+</ul>
+<h3><a class="header" href="#example" id="example">Example</a></h3>
+<pre><code class="language-bash">#!/bin/bash
+function parse_args() {
+	while getopts &quot;f:c&quot; PARAM; do
+		case $PARAM in
+			f) echo &quot;GOT -f $OPTARG&quot;;;
+			c) echo &quot;GOT -c&quot;;;
+			*) echo &quot;ERR: print usage&quot;; exit 1;;
+		esac
+	done
+	# users responsibility to reset OPTIND
+	OPTIND=0
+}
+
+parse_args -f xxx -c
+parse_args -f yyy
+</code></pre>
 <h2><a class="header" href="#completion" id="completion">Completion</a></h2>
 <p>The <code>complete</code> builtin is used to interact with the completion system.</p>
 <pre><code class="language-bash">complete                    # print currently installed completion handler
@@ -253,7 +289,7 @@ COMPREPLY       # array with possible completions
 </code></pre>
 <p>The <code>compgen</code> builtin is used to generate possible matches by comparing <code>word</code>
 against words generated by <code>option</code>.</p>
-<pre><code class="language-bash">compgen [option] [word]
+<pre><code class="language-bash">compgen &lt;option&gt; &lt;word&gt;
 
 # usefule options:
 # -W &lt;list&gt;    specify list of possible completions
@@ -268,7 +304,7 @@ compgen -W &quot;foo foobar bar&quot; &quot;f&quot;
 # compare &quot;hom&quot; against file/dir names and generate matches
 compgen -d -f &quot;hom&quot;
 </code></pre>
-<h3><a class="header" href="#example" id="example">Example</a></h3>
+<h3><a class="header" href="#example-1" id="example-1">Example</a></h3>
 <p>Skeleton to copy/paste for writing simple completions.</p>
 <p>Assume a program <code>foo</code> with the following interface:</p>
 <pre><code class="language-bash">foo -c green|red|blue -s low|high -f &lt;file&gt; -h
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