https://www.codrut.pro/tags/envsubst/ Recent content in Envsubst on Codrut Constantin Gusoi Hugo en Fri, 12 Jun 2020 22:29:13 +0000 https://www.codrut.pro/snippets/how-to-use-envsubst/ Fri, 12 Jun 2020 22:29:13 +0000 https://www.codrut.pro/snippets/how-to-use-envsubst/ <h2 id="install"> Install <a class="heading-link" href="#install"> <i class="fa fa-link" aria-hidden="true" title="Link to heading"></i> <span class="sr-only">Link to heading</span> </a> </h2> <div class="highlight"><pre tabindex="0" style="color:#f8f8f2;background-color:#272822;-moz-tab-size:4;-o-tab-size:4;tab-size:4;"><code class="language-sh" data-lang="sh"><span style="display:flex;"><span><span style="color:#75715e"># Manjaro / Arch</span> </span></span><span style="display:flex;"><span>sudo pacman -S gettext </span></span><span style="display:flex;"><span> </span></span><span style="display:flex;"><span><span style="color:#75715e"># Alpine</span> </span></span><span style="display:flex;"><span>apk add --update gettext </span></span></code></pre></div><h2 id="usage"> Usage <a class="heading-link" href="#usage"> <i class="fa fa-link" aria-hidden="true" title="Link to heading"></i> <span class="sr-only">Link to heading</span> </a> </h2> <p>Create a template input file <code>./truth.template</code> containing:</p> <div class="highlight"><pre tabindex="0" style="color:#f8f8f2;background-color:#272822;-moz-tab-size:4;-o-tab-size:4;tab-size:4;"><code class="language-sh" data-lang="sh"><span style="display:flex;"><span>Pizza is <span style="color:#e6db74">${</span>WHAT<span style="color:#e6db74">}</span> </span></span></code></pre></div><p>Export your environment variable:</p> <div class="highlight"><pre tabindex="0" style="color:#f8f8f2;background-color:#272822;-moz-tab-size:4;-o-tab-size:4;tab-size:4;"><code class="language-sh" data-lang="sh"><span style="display:flex;"><span>export WHAT<span style="color:#f92672">=</span>love </span></span></code></pre></div><p>Substitute it inside an output file:</p> <div class="highlight"><pre tabindex="0" style="color:#f8f8f2;background-color:#272822;-moz-tab-size:4;-o-tab-size:4;tab-size:4;"><code class="language-sh" data-lang="sh"><span style="display:flex;"><span>envsubst &lt; ./truth.template &gt; ./output.file </span></span></code></pre></div><p>You can see the result:</p> <div class="highlight"><pre tabindex="0" style="color:#f8f8f2;background-color:#272822;-moz-tab-size:4;-o-tab-size:4;tab-size:4;"><code class="language-sh" data-lang="sh"><span style="display:flex;"><span>cat ./output.file </span></span><span style="display:flex;"><span><span style="color:#75715e"># Pizza is love</span> </span></span></code></pre></div><h2 id="real-world-usage"> Real world usage <a class="heading-link" href="#real-world-usage"> <i class="fa fa-link" aria-hidden="true" title="Link to heading"></i> <span class="sr-only">Link to heading</span> </a> </h2> <p>Use it to generate random passwords and save them in env files:</p>