node-red/nodes/core/core/75-exec.html

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<script type="text/x-red" data-template-name="exec">
    <div class="form-row">
        <label for="node-input-command"><i class="fa fa-file"></i> <span data-i18n="exec.label.command"></span></label>
        <input type="text" id="node-input-command" data-i18n="[placeholder]exec.label.command">
    </div>
    <div class="form-row">
        <label><i class="fa fa-plus"></i> <span data-i18n="exec.label.append"></span></label>
        <input type="checkbox" id="node-input-addpay" style="display: inline-block; width: auto; vertical-align: top;">
        &nbsp;msg.payload
    </div>
    <div class="form-row">
        <label for="node-input-append"> </label>
        <input type="text" id="node-input-append" data-i18n="[placeholder]exec.placeholder.extraparams">
    </div>
    <div class="form-row">
        <label>&nbsp;</label>
        <input type="checkbox" id="node-input-useSpawn" placeholder="spawn" style="display: inline-block; width: auto; vertical-align: top;">
        <label for="node-input-useSpawn" style="width:70%;"><span data-i18n="exec.spawn"></span></label>
    </div>
    <div class="form-row">
        <label for="node-input-timer"><i class="fa fa-clock-o"></i> <span data-i18n="exec.label.timeout"></span></label>
        <input type="text" id="node-input-timer" style="width:65px;" data-i18n="[placeholder]exec.label.timeoutplace"> seconds
    </div>
    <div class="form-row">
        <label for="node-input-name"><i class="fa fa-tag"></i> <span data-i18n="common.label.name"></span></label>
        <input type="text" id="node-input-name" data-i18n="[placeholder]common.label.name">
    </div>
</script>

<script type="text/x-red" data-help-name="exec">
    <p>Calls out to a system command.<br/></p>
    <p>Provides 3 outputs: stdout, stderr, and return code.</p>
    <p>By default uses the <code>exec</code> system call which calls the command, then gets a callback
    on completion, returning stdout as the payload to the first, the error code as the third
    and, if available, stderr to the second output. If no error occurred, a zero is returned on the third output.</p>
    <p>Optionally can use <code>spawn</code> instead, which returns the output from stdout and stderr
    as the command runs (usually one line at a time). On completion it then returns a return code
    (on the 3rd output).</p>
    <p>The <code>exec</code> method spawns a subshell and therefore can be used for more complicated
    commands involving pipes. However, it waits for completion of the whole command before returing anything.</p> 
    <p>The optional append gets added to the command after <code>msg.payload</code> - so you can do
    things like pipe the result to another command.</p>
    <p>Commands or parameters with spaces should be enclosed in quotes - <i>"This is a single parameter"</i></p>
    <p>If stdout is binary a <i>buffer</i> is returned - otherwise returns a <i>string</i>.</p>
    <p>The blue status icon will be visible while the node is active.</p>
    <p>If running a Python app you may need to use the <code>-u</code> parameter to stop the output being buffered.</p>
</script>

<script type="text/javascript">
    RED.nodes.registerType('exec',{
        category: 'advanced-function',
        color:"darksalmon",
        defaults: {
            command: {value:"",required:true},
            addpay: {value:true},
            append: {value:""},
            useSpawn: {value:""},
            timer: {value:""},
            name: {value:""}
        },
        inputs:1,
        outputs:3,
        icon: "arrow-in.png",
        align: "right",
        label: function() {
            return this.name||this.command;
        },
        labelStyle: function() {
            return this.name?"node_label_italic":"";
        }
    });
</script>