User privileges enumerating serial device

Question

I'm trying to use the Java Simple Serial Connector on Arch Linux. I have a simple program listed below:

import jssc._

object Main {
  def main(args:Array[String]):Unit = {
    println("Started")
    val portNames = SerialPortList.getPortNames
    portNames.foreach(println(_))
  }
}

If I run ls -la /dev/ttyACM0 I get the following:

crw-rw---- 1 root uucp 166, 0 May  5 18:41 /dev/ttyACM0

If I run groups ryan I get uucp ryan

If I run sbt run I get just the line Started

If I run sudo sbt run I get the following:

Started
/dev/ttyACM0

I've added my user ryan to the uucp group, which owns /dev/ttyACM0, the device I'm trying to communicate with. What else could be preventing my program from enumerating the device?

Did you log out and log back in (needed for group changes to take effect) ? — , May 05 '14 at 23:05
...nope, forgot to do that! If you repost as an answer I'll mark it. — Ryan Kennedy, May 05 '14 at 23:08

score 2 · Accepted Answer · answered May 05 '14 at 23:19

You forgot to log out and log back in after adding yourself to the uucp group, which is necessary for group changes to take effect.

Here's an article about permissions and groups on the Archlinux wiki, in case you need more info.

User privileges enumerating serial device

1 Answers1