Virtual COM port on Linux

Stuart Jansen sjansen at
Mon Mar 15 14:09:17 MDT 2010

On Mon, 2010-03-15 at 13:58 -0600, Dave Smith wrote:
> Andrew McNabb wrote:
> > This is exactly why I only use shell scripts for very simple tasks. :)
> Well, I got it to work, and I learned something about command line 
> argument parsing in the process. Here's what I ended up with, and I 
> looked over it, and it was good:
>    # cat reboot-cable-modem
>    #!/bin/bash
>    device=/dev/ttyUSB0
>    printf '\xFF\x01\x01' >$device # Power off
>    sleep 10
>    printf '\xFF\x01\x00' >$device # Power on

commit 6ec863c7e6ff94b59b01a16459f04de41fba4e86
Author: Stuart Jansen <sjansen at>
Date:   Mon Mar 15 14:07:36 2010 -0600

    Converted reboot-cable-modem to use more idiomatic Bash

    * Don't write Perl like C, and don't write Bash like Python.
      - Uppercase variable names
      - Plenty of whitespace
    * Stuarts Rule of Shell Variables: Always quote variable
      unless you have a very, very good reason not to.


printf '\xFF\x01\x01' > "$DEVICE" # Power off
sleep "$DELAY"
printf '\xFF\x01\x00' > "$DEVICE" # Power on

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