57 lines
1.5 KiB
HTML
57 lines
1.5 KiB
HTML
---
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layout: page
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author: Alessandro Luini
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category-page: advanced
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category-title: Advanced commands
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tags: translate
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title: tr
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previous-page: pages/cmd/advanced/pipes.html
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next-page: pages/cmd/advanced/vi.html
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---
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The <code>tr</code> command in Unix-like operating systems, which name stands for
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<i>TRanslate</i> or <i>TRansliterate</i>, indicating its operation of replacing or removing
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specific characters in its input data set.
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<h3>How to use</h3>
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The utility reads a byte stream from its standard input and writes the
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result to the standard output. As arguments, it takes two sets of
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characters (generally of the same length), and replaces occurrences of
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the characters in the first set with the corresponding elements from the
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second set.<br>
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For example,
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<pre>
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tr 'abcd' 'jkmn'
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</pre>
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would maps all characters a to j, b to k, c to m, and d to n.<br>
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The character set may be abbreviated by using character ranges. The
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previous example could be also written as:
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<pre>
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tr 'a-d' 'jkmn'
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</pre>
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<h3>Flags</h3>
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<ul>
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<li> <b>-s</b>: The s flag causes tr to compress sequences of identical
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adjacent characters in its output to a single token.
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<pre>
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tr -s '\n'
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</pre>
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replaces sequences of one or more newline characters with a single
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newline.
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</li>
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<li> <b>-d</b>: The d flag causes tr to delete all tokens of the specified
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set of characters from its input. In this case, only a single character
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set argument is used. The following command removes carriage return
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characters.
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<pre>
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tr -d '\r'
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</pre>
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</li>
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</ul>
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