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After go1.16, go will use module mode by default, even when the repository is checked out under GOPATH or in a one-off directory. Add go.mod, go.sum to keep this repo buildable without opting out of the module mode. > go mod init github.com/mmcgrana/gobyexample > go mod tidy > go mod vendor In module mode, the 'vendor' directory is special and its contents will be actively maintained by the go command. pygments aren't the dependency the go will know about, so it will delete the contents from vendor directory. Move it to `third_party` directory now. And, vendor the blackfriday package. Note: the tutorial contents are not affected by the change in go1.16 because all the examples in this tutorial ask users to run the go command with the explicit list of files to be compiled (e.g. `go run hello-world.go` or `go build command-line-arguments.go`). When the source list is provided, the go command does not have to compute the build list and whether it's running in GOPATH mode or module mode becomes irrelevant.
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178 lines
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<!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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}
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if (e.key == "ArrowRight") {
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window.location.href = 'command-line-flags';
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}
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}
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</script>
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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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<div class="highlight"><pre><span class="kn">package</span> <span class="nx">main</span>
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</pre></div>
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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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<div class="highlight"><pre><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></div>
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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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<div class="highlight"><pre><span class="kd">func</span> <span class="nx">main</span><span class="p">()</span> <span class="p">{</span>
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</pre></div>
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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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<div class="highlight"><pre> <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></div>
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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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<div class="highlight"><pre> <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></div>
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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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<div class="highlight"><pre> <span class="nx">fmt</span><span class="p">.</span><span class="nx">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="nx">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="nx">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></div>
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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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<div class="highlight"><pre><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] </span>
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<span class="go">[a b c d]</span>
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<span class="go">c</span>
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</pre></div>
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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> | <a href="https://github.com/mmcgrana/gobyexample/blob/master/examples/command-line-arguments">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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<script src="site.js" async></script>
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</body>
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</html>
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