EVOLUTION-MANAGER
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} code > span.ot { color: #007020; } code > span.al { color: #ff0000; font-weight: bold; } code > span.fu { color: #900; font-weight: bold; } code > span.er { color: #a61717; background-color: #e3d2d2; } </style> </head> <body> <h1 class="title toc-ignore">Interacting with Terminals</h1> <p>The <code>rstudioapi</code> package provides a collection of functions that can be used to interact with the <a href="https://support.rstudio.com/hc/en-us/articles/115010737148-Using-the-RStudio-Terminal">RStudio terminal tab</a>.</p> <p>There are two primary approaches to using these functions.</p> <ol style="list-style-type: decimal"> <li><p>Use <code>terminalExecute()</code> to run a specific process with the output shown in a new terminal buffer, without blocking the current R session.</p></li> <li><p>Create, query, and manipulate interactive terminals. This might be used to develop custom terminal behavior via an <a href="https://rstudio.github.io/rstudioaddins/">RStudio addin</a>.</p></li> </ol> <div id="terminalexecute-scenario" class="section level2"> <h2>TerminalExecute Scenario</h2> <div class="sourceCode" id="cb1"><pre class="sourceCode r"><code class="sourceCode r"><span id="cb1-1"><a href="#cb1-1"></a><span class="co"># Start a command with results displayed in a terminal buffer</span></span> <span id="cb1-2"><a href="#cb1-2"></a>termId <-<span class="st"> </span>rstudioapi<span class="op">::</span><span class="kw">terminalExecute</span>(<span class="st">"ping rstudio.com"</span>)</span> <span id="cb1-3"><a href="#cb1-3"></a></span> <span id="cb1-4"><a href="#cb1-4"></a><span class="co"># If viewing the result in the terminal buffer is sufficient,</span></span> <span id="cb1-5"><a href="#cb1-5"></a><span class="co"># then no need to do anything else. The command will continue</span></span> <span id="cb1-6"><a href="#cb1-6"></a><span class="co"># running and displaying its results without blocking the R session.</span></span> <span id="cb1-7"><a href="#cb1-7"></a></span> <span id="cb1-8"><a href="#cb1-8"></a><span class="co"># To obtain the results programmatically, wait for it to finish.</span></span> <span id="cb1-9"><a href="#cb1-9"></a><span class="cf">while</span> (<span class="kw">is.null</span>(rstudioapi<span class="op">::</span><span class="kw">terminalExitCode</span>(termId))) {</span> <span id="cb1-10"><a href="#cb1-10"></a> <span class="kw">Sys.sleep</span>(<span class="fl">0.1</span>)</span> <span id="cb1-11"><a href="#cb1-11"></a>}</span> <span id="cb1-12"><a href="#cb1-12"></a></span> <span id="cb1-13"><a href="#cb1-13"></a>result <-<span class="st"> </span>rstudioapi<span class="op">::</span><span class="kw">terminalBuffer</span>(termId)</span> <span id="cb1-14"><a href="#cb1-14"></a></span> <span id="cb1-15"><a href="#cb1-15"></a><span class="co"># Delete the buffer and close the session in the IDE</span></span> <span id="cb1-16"><a href="#cb1-16"></a>rstudioapi<span class="op">::</span><span class="kw">terminalKill</span>(termId)</span></code></pre></div> </div> <div id="interative-terminal-scenario" class="section level2"> <h2>Interative Terminal Scenario</h2> <p>Several concepts are important to understand to make full use of these functions.</p> <div id="terminal-identifier" class="section level3"> <h3>Terminal Identifier</h3> <p>Each terminal session has a unique <strong>terminal identifier</strong>, a required argument for most of the functions. A terminal identifier is generated and returned when a terminal is created via <code>terminalCreate()</code> or <code>terminalExecute()</code>, and identifiers of existing terminals can be obtained via <code>terminalList()</code> or <code>terminalVisible()</code>.</p> </div> <div id="terminal-session" class="section level3"> <h3>Terminal Session</h3> <p>A <strong>terminal session</strong> is an instance of a terminal that can be displayed in the RStudio terminal tab. A terminal session consists of:</p> <ul> <li>a unique terminal identifier</li> <li>a unique caption shown in the RStudio terminal dropdown (e.g. “Terminal 1”)</li> <li>a shell process (e.g. bash) running as a child process of the R session</li> <li>zero or more processes running as children of the shell (e.g. commands)</li> <li>an xterm-compatible terminal emulator in the terminal tab</li> <li>a buffer of output shown in the terminal emulator (can be cleared via <code>terminalClear()</code>)</li> </ul> </div> <div id="busy-terminal" class="section level3"> <h3>Busy Terminal</h3> <p>A terminal session with child processes running (excluding the shell), is considered <strong>busy</strong> and this is reflected in the IDE UI and can be queried with <code>terminalBusy()</code>.</p> </div> <div id="terminal-states" class="section level3"> <h3>Terminal States</h3> <p>In the most common situation, a terminal session has all the above features; however, it is possible for terminals to be in other states.</p> <p><strong>No shell process or child processes</strong>: This happens if the associated R session has been closed (or suspended in the case of an inactive RStudio Server session).</p> <p>The <code>terminalRunning()</code> function returns <code>TRUE</code> if a terminal is in this state.</p> <p>If a terminal is not running, it can be started via interacting with it in the RStudio IDE, or via <code>terminalActivate()</code>.</p> <div class="sourceCode" id="cb2"><pre class="sourceCode r"><code class="sourceCode r"><span id="cb2-1"><a href="#cb2-1"></a><span class="co"># start an interactive terminal using the shell selected in </span></span> <span id="cb2-2"><a href="#cb2-2"></a><span class="co"># RStudio global options</span></span> <span id="cb2-3"><a href="#cb2-3"></a>myTerm <-<span class="st"> </span>rstudioapi<span class="op">::</span><span class="kw">terminalCreate</span>()</span> <span id="cb2-4"><a href="#cb2-4"></a></span> <span id="cb2-5"><a href="#cb2-5"></a><span class="co"># ....</span></span> <span id="cb2-6"><a href="#cb2-6"></a><span class="co"># sometime later</span></span> <span id="cb2-7"><a href="#cb2-7"></a><span class="co"># ....</span></span> <span id="cb2-8"><a href="#cb2-8"></a><span class="cf">if</span> (<span class="op">!</span>rstudioapi<span class="op">::</span><span class="kw">terminalRunning</span>(myTerm)) {</span> <span id="cb2-9"><a href="#cb2-9"></a> <span class="co"># start the terminal shell back up, but don't bring to front</span></span> <span id="cb2-10"><a href="#cb2-10"></a> rstudioapi<span class="op">::</span><span class="kw">terminalActivate</span>(myTerm, <span class="dt">show =</span> <span class="ot">FALSE</span>)</span> <span id="cb2-11"><a href="#cb2-11"></a> </span> <span id="cb2-12"><a href="#cb2-12"></a> <span class="co"># wait for it to start</span></span> <span id="cb2-13"><a href="#cb2-13"></a> <span class="cf">while</span> (<span class="op">!</span>rstudioapi<span class="op">::</span><span class="kw">terminalRunning</span>(myTerm)) {</span> <span id="cb2-14"><a href="#cb2-14"></a> <span class="kw">Sys.sleep</span>(<span class="fl">0.1</span>)</span> <span id="cb2-15"><a href="#cb2-15"></a> }</span> <span id="cb2-16"><a href="#cb2-16"></a> </span> <span id="cb2-17"><a href="#cb2-17"></a> <span class="co"># send a new command </span></span> <span id="cb2-18"><a href="#cb2-18"></a> rstudioapi<span class="op">::</span><span class="kw">terminalSend</span>(myTerm, <span class="st">"echo Hello</span><span class="ch">\n</span><span class="st">"</span>) </span> <span id="cb2-19"><a href="#cb2-19"></a>}</span></code></pre></div> <p><strong>Running but not loaded in the IDE</strong>: On RStudio Server, the web browser can be closed but the R session and any associated terminal sessions keep running. If the web browser is reconnected, each terminal will be redisplayed in the IDE when it is selected. The <code>rstudioapi</code> functions may be used on a terminal in this state; for example, the buffer may still be fetched with <code>terminalBuffer()</code> even if the terminal isn’t loaded in the IDE (so long as the R session is still alive).</p> <p><strong>Terminated but still visible</strong>: Normally the terminal emulator for a given terminal session will close when the shell exits. If the option <strong>Close Terminal When Shell Exits</strong> is turned off, then the terminal buffer will remain loaded in the RStudio IDE until closed by the user or <code>terminalKill()</code>. Terminals started with <code>terminalExecute()</code> will always remain loaded when they finish running. To test a terminal for this state, <code>terminalExitCode()</code> will return a non-NULL value.</p> </div> </div> <!-- code folding --> <!-- dynamically load mathjax for compatibility with self-contained --> <script> (function () { var script = document.createElement("script"); script.type = "text/javascript"; script.src = "https://mathjax.rstudio.com/latest/MathJax.js?config=TeX-AMS-MML_HTMLorMML"; document.getElementsByTagName("head")[0].appendChild(script); })(); </script> </body> </html>