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git-svn-id: svn+ssh://atelier.inf.usi.ch/home/bevilj/group-1@105 a672b425-5310-4d7a-af5c-997e18724b81
69 lines
1.4 KiB
HTML
69 lines
1.4 KiB
HTML
---
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layout: page
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author: Domenico Votta
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category-page: advanced
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category-title: Advanced commands
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tags: number lines count
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title: nl
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---
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<p>The <code>nl</code> is a command that permits to number the lines. Through some flags you can decide how to filter this command.</p>
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We have a file named <code>example.txt</code> that contains 5 elements, to test this command:
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{% highlight bash linenos %}
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Car
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Computer
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Robot
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Smartphone
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Videogame
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{% endhighlight %}
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The syntax command is:
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<pre> nl [flags][file] </pre>
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<pre>
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nl example.txt
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1 Car
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2 Computer
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3 Robot
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4 Smartphone
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5 Videogame
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</pre>
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<p>How you can see the command has numbered the lines.</p>
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<h2>Flags</h2>
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<p>Here a list that contains the main flags of these command:
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<ul>
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<li> <b>-b</b>: Specify the lines to be numered </li>
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<pre>
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nl -b p^[cv] example.txt
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1 Car
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2 Computer
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3 Videogame
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Robot
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Smartphone
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</pre>
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<p> <code>p^[cv]</code> says to nl to number only the lines that start with c and v.</p>
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<li> -b<b>n</b>: The flag n goes with b, doesn't number any lines </li>
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<pre>
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nl -bn example.txt
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Car
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Computer
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Videogame
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Robot
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Smartphone
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</pre>
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<li> <b>-s</b>: Usually nl separes the number of the line from the text with a tab, with -s flag you can choose another separator, in this example we will use "=". </li>
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<pre>
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nl -s= example.txt
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1=Car
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2=Computer
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3=Videogame
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4=Robot
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5=Smartphone
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</pre>
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</ul>
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</p>
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