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What does pts/2 indicate in the output below? Why there is no such for other dd processes?

$ ps -aef |grep dd
    root  6553672 15073352   3 02:32:19      -  0:01 dd of=/dev/lv01 bs=1024k
  padmin  9437410 16515110   1 02:43:32  pts/2  0:00 grep dd
    root 13828156 11010220   0 02:32:33      -  0:00 dd of=/dev/lv02 bs=1024k
    root 14155860 13828156   2 02:32:33      -  0:01 dd of=/dev/lv02 bs=1024k
    root 15073352 13762812   0 02:32:19      -  0:00 dd of=/dev/lv01 bs=1024k
    root 15532200 15925276   2 02:40:47  pts/1  0:03 dd of=/home/padmin/samp

2 Answers 2

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pts is a pseudoterminal, or a non-physical terminal, as opposed to tty which usually stands for a physical terminal devices.

The most common pts devices are SSH sessions.

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  • Aren't pseudo-terminals usually called pty?
    – Daniel Beck
    Aug 11, 2013 at 16:26
  • Agree with you somewhat, but the one without pts are those initiated throw remote application. The one with pts are initiated from the command dd of=/dev/ex1 bs=1024k through command line.
    – Ratnakar
    Aug 12, 2013 at 12:46
  • And is there any priority given to those with pts?
    – Ratnakar
    Aug 12, 2013 at 12:47
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These are most likely a result of cronjobs (or at jobs, other timed jobs) that don't have a terminal attached. Since cron is a daemon process, (nearly) by definition it doesn't have a terminal. Any child processes will inherit that no-terminal state

THe padmin job and the latter root job seem to be kicked off manually by people/processes in a terminal window.

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  • Yes Rich. I did in a terminal window. Is there any priority given to these?
    – Ratnakar
    Aug 12, 2013 at 12:54
  • @Ratnakar not sure what you mean. You can change the CPU/scheduler priority of a process with renice. Only root can renice with a negative value i.e. give the process higher runtime priority. Is this what you want? Aug 12, 2013 at 14:27

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