175 lines
5.9 KiB
Plaintext
Generated
175 lines
5.9 KiB
Plaintext
Generated
<!DOCTYPE html>
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<html>
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<head>
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<meta charset="utf-8">
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<title>Go by Example: Command-Line Arguments</title>
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<link rel=stylesheet href="site.css">
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</head>
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<script>
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onkeydown = (e) => {
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if (e.key == "ArrowLeft") {
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window.location.href = 'testing';
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window.location.href = 'command-line-flags';
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<body>
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<div class="example" id="command-line-arguments">
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<h2><a href="./">Go by Example</a>: Command-Line Arguments</h2>
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<table>
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<tr>
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<td class="docs">
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<p><a href="http://en.wikipedia.org/wiki/Command-line_interface#Arguments"><em>Command-line arguments</em></a>
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are a common way to parameterize execution of programs.
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For example, <code>go run hello.go</code> uses <code>run</code> and
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<code>hello.go</code> arguments to the <code>go</code> program.</p>
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</td>
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<td class="code empty leading">
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</td>
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</tr>
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<tr>
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<td class="docs">
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</td>
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<td class="code leading">
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<a href="http://play.golang.org/p/oSxtj7v_v1K"><img title="Run code" src="play.png" class="run" /></a><img title="Copy code" src="clipboard.png" class="copy" />
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<pre class="chroma"><span class="kn">package</span> <span class="nx">main</span>
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</pre>
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</td>
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</tr>
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<tr>
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<td class="docs">
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</td>
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<td class="code leading">
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<pre class="chroma"><span class="kn">import</span> <span class="p">(</span>
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<span class="s">"fmt"</span>
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<span class="s">"os"</span>
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<span class="p">)</span>
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</pre>
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</td>
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</tr>
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<tr>
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<td class="docs">
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</td>
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<td class="code leading">
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<pre class="chroma"><span class="kd">func</span> <span class="nf">main</span><span class="p">()</span> <span class="p">{</span>
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</pre>
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</td>
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</tr>
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<tr>
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<td class="docs">
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<p><code>os.Args</code> provides access to raw command-line
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arguments. Note that the first value in this slice
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is the path to the program, and <code>os.Args[1:]</code>
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holds the arguments to the program.</p>
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</td>
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<td class="code leading">
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<pre class="chroma">
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<span class="nx">argsWithProg</span> <span class="o">:=</span> <span class="nx">os</span><span class="p">.</span><span class="nx">Args</span>
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<span class="nx">argsWithoutProg</span> <span class="o">:=</span> <span class="nx">os</span><span class="p">.</span><span class="nx">Args</span><span class="p">[</span><span class="mi">1</span><span class="p">:]</span>
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</pre>
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</td>
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</tr>
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<tr>
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<td class="docs">
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<p>You can get individual args with normal indexing.</p>
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</td>
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<td class="code leading">
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<pre class="chroma">
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<span class="nx">arg</span> <span class="o">:=</span> <span class="nx">os</span><span class="p">.</span><span class="nx">Args</span><span class="p">[</span><span class="mi">3</span><span class="p">]</span>
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</pre>
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</td>
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</tr>
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<tr>
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<td class="docs">
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</td>
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<td class="code">
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<pre class="chroma"> <span class="nx">fmt</span><span class="p">.</span><span class="nf">Println</span><span class="p">(</span><span class="nx">argsWithProg</span><span class="p">)</span>
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<span class="nx">fmt</span><span class="p">.</span><span class="nf">Println</span><span class="p">(</span><span class="nx">argsWithoutProg</span><span class="p">)</span>
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<span class="nx">fmt</span><span class="p">.</span><span class="nf">Println</span><span class="p">(</span><span class="nx">arg</span><span class="p">)</span>
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<span class="p">}</span>
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</pre>
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</td>
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</tr>
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</table>
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<table>
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<tr>
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<td class="docs">
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<p>To experiment with command-line arguments it’s best to
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build a binary with <code>go build</code> first.</p>
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</td>
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<td class="code leading">
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<pre class="chroma">
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<span class="gp">$</span> go build command-line-arguments.go
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<span class="gp">$</span> ./command-line-arguments a b c d
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<span class="go">[./command-line-arguments a b c d]
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</span><span class="go">[a b c d]
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</span><span class="go">c</span></pre>
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</td>
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</tr>
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<tr>
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<td class="docs">
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<p>Next we’ll look at more advanced command-line processing
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with flags.</p>
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</td>
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<td class="code empty">
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</td>
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</tr>
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</table>
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<p class="next">
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Next example: <a href="command-line-flags">Command-Line Flags</a>.
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</p>
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<p class="footer">
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by <a href="https://markmcgranaghan.com">Mark McGranaghan</a> and <a href="https://eli.thegreenplace.net">Eli Bendersky</a> | <a href="https://github.com/mmcgrana/gobyexample">source</a> | <a href="https://github.com/mmcgrana/gobyexample#license">license</a>
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</p>
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</div>
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<script>
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var codeLines = [];
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codeLines.push('');codeLines.push('package main\u000A');codeLines.push('import (\u000A \"fmt\"\u000A \"os\"\u000A)\u000A');codeLines.push('func main() {\u000A');codeLines.push(' argsWithProg :\u003D os.Args\u000A argsWithoutProg :\u003D os.Args[1:]\u000A');codeLines.push(' arg :\u003D os.Args[3]\u000A');codeLines.push(' fmt.Println(argsWithProg)\u000A fmt.Println(argsWithoutProg)\u000A fmt.Println(arg)\u000A}\u000A');codeLines.push('');codeLines.push('');
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