How to continuously read from the STDOUT of a system command?

<p>I&#39;d like to wrap the &#34;tail -f&#34; command for monitoring live file changes. I&#39;m trying to read and handle each update to the stdout from tail -f and handle it. All the examples I see online are related to reading from STDOUT once from a command. I have not a clue of how I can go about doing this? Any ideas/recommendations/links? I&#39;m grateful for any insight on this.</p> <p>Thanks</p> <hr/>**评论：**<br/><br/>lstokeworth: <pre><p>A very simple way to tail a file is:</p> <pre><code>buf := make([]byte, 1024) for { n, err := f.Read(buf) if n &gt; 0 { // do something with buf[:n] } if err == io.EOF { time.Sleep(time.Second) } else if err != nil { // handle error break } } </code></pre> <p>Adjust the sleep time up or down to taste.</p></pre>raff99: <pre><p>And that is, at the core, what &#34;tail -f&#34; does so you may want to just roll your own all in Go instead of trying to &#34;tail the tail&#34;</p></pre>Ajpennster: <pre><p>This is a pretty good approach. I may end up using this. Thanks</p></pre>earthboundkid: <pre><p>This feels like a classic <a href="http://xyproblem.info" rel="nofollow">XY problem</a>.</p></pre>djherbis: <pre><p>You might actually be interesting in something like: <a href="https://gopkg.in/fsnotify.v1" rel="nofollow">https://gopkg.in/fsnotify.v1</a></p></pre>Ajpennster: <pre><p>Thanks for the share. I&#39;ll definitely look into it but I&#39;d prefer a solution that only requires the standard library. I&#39;d also like to wrap &#34;tail -f file.txt&#34; instead of &#34;reinventing the wheel&#34;</p></pre>djherbis: <pre><p>StdoutPipe is what you want (as JRMWarfare says). However, if you want to act on each &#34;update&#34; it would probably be easier to use a library like fsnotify.</p> <p>If all you want to do is redirect the bytes of the output somewhere else, then StdoutPipe will work.</p> <p>Trying to detect each update via StdoutPipe will be hard since you&#39;ll just be getting a stream of bytes, you won&#39;t really get &#34;updates&#34; you&#39;ll just read more bytes.</p></pre>Ajpennster: <pre><p>I was thinking along those lines, reading every time stdout had bytes but I was a bit lost on how I&#39;d achieve that. Most examples I&#39;ve found were reading only once.</p></pre>sleepydog: <pre><p><a href="https://golang.org/pkg/bufio/#example_Scanner_lines" rel="nofollow">https://golang.org/pkg/bufio/#example_Scanner_lines</a></p></pre>JRMWarfare: <pre><p>os/exec has <a href="https://golang.org/pkg/os/exec/#Cmd.StdoutPipe" rel="nofollow">StdoutPipe</a>, which seems appropriate for what you&#39;re trying to do.</p> <p>If I were you I would kick off a groutine where with a loop to monitor the pipe from the command which would write the output to a channel consumed by your primary operations.</p></pre>