Golang get command tty output

Question

I'm using go's exec Run command to get command output, which works great when the command 'Stdout' field is set to os.Stdout, and the error is sent to os.Stderr.

I want to display the output and the error output to the console, but I also want my program to see what the output was.

I then made my own Writer type that did just that, wrote both to a buffer and printed to the terminal.

Here's the problem—some applications change their output to something much less readable by humans when it detects it's not writing to a tty. So the output I get changes to something ugly when I do it in the latter way. (cleaner for computers, uglier for humans)

I wanted to know if there was some way within Go to convince whatever command I'm running that I am a tty, despite not being os.Stdout/os.Stderr. I know it's possible to do using the script bash command, but that uses a different flag depending on Darwin/Linux, so I'm trying to avoid that.

Thanks in advance!

kostix · Accepted Answer · 2019-09-20 18:06:02Z

5

The only practical way to solve this is to allocate a pseudo terminal (PTY) and make your external process use it for its output: since PTY is still a terminal, a process checking whether it's connected to a real terminal thinks it is.

You may start with this query.

The github.com/creack/ptyis probably a good starting point.

The next step is to have a package implementing a PTY actually allocate it, and connect "the other end" of a PTY to your custom writer.

(By the way, there's no point in writing a custom "multi writer" as there exist io.MultiWriter).

answered Sep 20, 2019 at 18:06

kostix

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