https://blog.foamzou.com/tags/shell/ Recent content in Shell on Foam 的博客 Hugo zh-cn Mon, 20 Dec 2021 14:13:36 +0800 https://blog.foamzou.com/posts/shell-skill/ Mon, 20 Dec 2021 14:13:36 +0800 https://blog.foamzou.com/posts/shell-skill/ <h2 id="文本处理">文本处理</h2> <h3 id="清除每行头尾部的空白符">清除每行头&amp;尾部的空白符</h3> <div class="highlight"><pre tabindex="0" class="chroma"><code class="language-fallback" data-lang="fallback"><span class="line"><span class="cl">awk &#39;{$1=$1;print}&#39; </span></span></code></pre></div><p>ref: <a href="https://stackoverflow.com/questions/448005/whats-an-easy-way-to-read-random-line-from-a-file">https://stackoverflow.com/questions/448005/whats-an-easy-way-to-read-random-line-from-a-file</a></p> <h3 id="在一个文本随机选取若干行">在一个文本随机选取若干行</h3> <div class="highlight"><pre tabindex="0" class="chroma"><code class="language-fallback" data-lang="fallback"><span class="line"><span class="cl">// macos 则先 brew install coreutils，然后用 gshuf </span></span><span class="line"><span class="cl">shuf foo.txt | head -n 100 </span></span></code></pre></div><div class="highlight"><pre tabindex="0" class="chroma"><code class="language-fallback" data-lang="fallback"><span class="line"><span class="cl">cat foo.txt | awk &#39;BEGIN{srand();}{print rand()&#34;\t&#34;$0}&#39; | sort -k1 -n | cut -f2- | head -n 100 </span></span></code></pre></div><p>ref: <a href="https://stackoverflow.com/questions/448005/whats-an-easy-way-to-read-random-line-from-a-file">https://stackoverflow.com/questions/448005/whats-an-easy-way-to-read-random-line-from-a-file</a></p> <h3 id="截取每行的前几个字符">截取每行的前几个字符</h3> <div class="highlight"><pre tabindex="0" class="chroma"><code class="language-fallback" data-lang="fallback"><span class="line"><span class="cl">cut -c 1-3 file // 前三个字符 </span></span></code></pre></div><p>ref: <a href="https://stackoverflow.com/questions/19869511/how-to-restrict-length-of-string-present-in-a-line-using-linux">https://stackoverflow.com/questions/19869511/how-to-restrict-length-of-string-present-in-a-line-using-linux</a></p>