question on pts and pty
 

Hi,

Looking at man pages of pts and pty it says:

It seems that they both deal with master slave channels. But, pts refers to /dev/ptmx which is a device file. What is really their difference? Could you please give me a simple clarification on these terms?

In early Unix systems the computer console was just lights and switches. If you wanted a keyboard and display (no mice then) you connected a terminal using a serial port. Those are long gone, but a lot of software still exists that expects to talk to a terminal. The master and slave you mention just emulate the two ends of that connection. When you open a bash window, the ps command shows a pts/0 which is the terminal end of the emulated serial connection. If you actually have a terminal it would be ttyS0. Opening ptmx is what creates a new pts when you start the terminal window. That saves you from having 256 pts in your dev directory and then having to search for a free one when you want to make a connection.