Quote:
Originally Posted by
pinga123
Hi ,
I have searched wiki for pseudo tty devices but it was very complex for me to understand.
A pseudo-TTY is it's a virtual device that acts like a terminal -- that is to say, acts like a serial port plus all the frills UNIX has added to them over the years with a keyboard and screen attached. You get features and side-effects like you'd expect of a real terminal: It can be configured to produce SIGINT when someone writes ctrl-C into it, you can configure it to echo its input or not, etc, etc. But it's not a real terminal -- it's a purely software thing. There's no real keyboard or screen involved anymore.
This is used for things like ssh, where you want to log into a real terminal but of course are too far away to do so. It opens a pseudo-terminal instead and just sends everything along.
Software can tell the difference between something that's a terminal and something that's not. Password inputs read only from a real TTY or a pseudo-tty for instance.