Pseudoterminals (also spelled “pseudotty” or “PTY”) are pseudo-devices used with ttys whose emulators run in userspace. Use [tag:tty] for broad (text terminal)-related questions, and [tag:console] for terminal devices pertaining to the system console.

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How to get the opened pty for a given background process (without login) in AIX

Using this answer http://unix.stackexchange.com/a/283521/114939 which allow us to find processes that keep an given pty opened without login (who command cannot show them), caused me to ask the ...
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Why are some pts in AIX never reused?

In an AIX system (AIX p740 1 7) that is running for about several months, some pts aren't reused anymore. This was noticed using the "who" command, with the following "awk" expression, running it ...
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Why doesn't sshd use a pseudo terminal when the ssh client's argument is followed by an interactive program?

The normal way to connect to an SSH server is ssh username@ip_address. But a user may only want to run a program on the remote machine. So the program name follows after the normal argument which is ...
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Terminal allocation breaks files while using ssh for transfer

I used ssh to untar a remote file using: ssh host "cat file.tgz" | tar xf - This works perfectly fine. However I noticed while playing with forced commands, that pty-allocation changes the output ...
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openpty returning zero as master file descriptor

I am opening a pseudoterminal with openpty function. This will be used to redirect some data coming from a serial port into an external application (in this case, a GPS receiver). The fact is that ...
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1answer
491 views

How to run builds in Docker containers from Jenkins

I am trying to use Jenkins to build a C++ project in a Docker container. I have no problem building in Jenkins, or building in a container outside of Jenkins. Below is what I tried. I am omitting the ...
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5answers
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How to trick a command into thinking its output is going to a terminal

Given a command that changes its behaviour when its output is going to a terminal (e.g. produce coloured output), how can that output be redirected in a pipeline while preserving the changed ...
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1answer
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Bash shell launched by forkpty() spawns child processes that ignore SIGINT. Why and how do I ensure SIGINT is not ignored?

I have a C program that uses forkpty to execute a bash shell. I'm finding that the programs launched by this shell are launched with SIGINT ignored, so when I send a Ctrl-C to the shell they never ...
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1answer
149 views

“No more PTYs” when starting screen as non root-user

Whenever I try to start a screen-session as a non-root-user I get "No more PTYs." as a response. Same command in the same directory as root works properly. I tried the solution from this post but it ...
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1answer
44 views

Using shared serial modem

I'm trying to use on Solaris box modem connected to Linux box via serial port. Sharing is made from socat. Server command(linux): socat tcp-l:54321,reuseaddr,fork ...
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2answers
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Wrapper to allocate a pty (opposite to nohup)

I have a command foo that (for reasons we need not go into) needs to have a pty allocated, i.e. foo succeeds but nohup foo fails. What is the easiest way to allocate a pty when there is not one? ...
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4answers
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Different behavior of tty's vs pty's

If I do man bash inside of X, e.g., in xterm or mate-terminal, I get some words underlined. If I do man bash in a virtual terminal, I get those same words colored. Can I get the same coloring in X? ...
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Mocking a pseudo tty (pts)

We would like to run some curses based apps in background. These apps use curses and get the current tty port name to be used internally to map log files and others context-terminal associations. ...
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1answer
200 views

How can I fix /dev/pts after mounting it?

I made the same mistake as in this question: Debian chroot blocking PTTYs on host I mounted a "devpts" filesystem inside a chroot, and now urxvt can't create ptys. Oddly enough xterm still can. ...
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1answer
277 views

Using cron to start a process on a terminal without using screen?

I want to start a process in a terminal using cron. I want the process to start in a terminal, so that I can continuously see the output of the process on the terminal, and kill it / restart it etc. I ...
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1answer
127 views

using a pty like a socket?

I'm writing a collection of scripts to talk to an external program. My problem is that the scripts are only "alive" for a short time (triggered by a keypress in a larger program) but the external ...
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Where can I find the speciation that a terminal emulator must meet?

I'm interested in writing a terminal emulator for fun. I roughly understand the division of labor between the shell and the terminal emulator from this post: What is the exact difference between a ...
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2answers
359 views

How are long command lines ( > $COLUMNS ) automatically wrapped to a new line?

There are several points where I/O is passed through, some of which (to my knowledge) are the shell, pty, tty, termios, terminal emulator application. In most terminal emulators, long command lines ...
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2answers
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Triggering zero-byte reads on FIFO/pty

I'd like to know how to emulate the ICANON behavior of ^D: namely, trigger an immediate, even zero-byte, read in the program on the other end of a FIFO or PTY or socket or somesuch. In particular, I ...
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1answer
67 views

Saving colored output regardless of the source

How can I save colored output to a file regardless of the source when the sources turn coloring off if they detect their stdout isn't a terminal?
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1answer
151 views

Attach tmux to pty after reptyr?

I've got reptyr to "open a new pty" by doing: reptyr -L 7969 where 7969 is the PID of rabbitmq-server. The output of reptyr is Opened a new pty: /dev/pts/25 but how do I attach tmux to that ...
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How do I come by this pty and what can I do with it?

It seems that a simple shell redirect from /dev/ptmx gets me a new pseudo-terminal. $ ls /dev/pts; ls /dev/pts </dev/ptmx 0 1 2 ptmx 0 1 2 3 ptmx It disappears as soon as the process that ...
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1answer
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Determine the owner of the session of a process

I am trying to implement a way to determine which user is owner of some process's session, in a way that's as cross-platform as possible. In Linux I can trace the process's pty by following the link ...
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2answers
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How do I preserve coloured output when piping to `less -R`?

$ ffmpeg -v debug ... Coloured output. $ ffmpeg -v debug ... |& less -R Dull output. How do I make the output coloured while piping it to something?
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How to capture data transferred on a PTY?

I am running NetBSD 6.1.4, and I have an stunnel instance with the following configuration: [https service] accept = 443 CAfile = /u01/usbtether/CA/certs/rootCA.crt cert = ...
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1answer
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How can I automatically interrupt what I'm doing to input something?

As per Nick Winter's The Motivation Hacker, I want to measure my happiness. I know that I'm bad at remembering things or responding to reminders, so I'd like to set up a daemon that, at random ...
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1answer
148 views

Is it possible to change what tty a terminal emulator is connected to?

If I have a terminal emulator (say, xterm) by default it connects to a pseudoterminal like /dev/pts/3 What I would like to know is if it is possible to connect it directly to, say, tty1? Could I ...
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How can we know who's at the other end of a pseudo-terminal device?

If I do a: echo foo > /dev/pts/12 Some process will read that foo\n from its file descriptor to the master side. Is there a way to find out what that(those) process(es) is(are)? Or in other ...
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4answers
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What are the responsibilities of each Pseudo-Terminal (PTY) component (software, master side, slave side)?

I am trying to figure out how a tty works1 (the work-flow and responsibilities of each elements). I have read several interesting articles about it, but there are still some blurry areas. This is ...
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2answers
1k views

Why root can't open pseudo terminal device? (permission denied)

Using a non-root user, I'm creating a pseudo terminal with socat like this: socat -d -d PTY,link=$HOME/.wine/dosdevices/com1,raw,echo=0 PTY,link=/tmp/com1-pty,raw,echo=0 and I need a root ...
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Which process is occupying a certain pseudo terminal pts/X?

On Linux: Normally pseudo terminals are allocated one after the other. Today I realized that even after a reboot of my laptop the first opened terminal window (which was always pts/0 earlier) ...
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Trying to understand how TTYs and PTYs work in CentOS 6.5? [duplicate]

I started to dig into the whole Linux pty and tty hell. I'm trying to understand how it works here in Linux so I was reading quite a lot of articles that covered this topic. So far I know: TTYs ...
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1answer
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What is the maximum allowed number of TTY, is it defined anywhere in kernel headers?

What's the maximum allowed number of TTYs? I found pty.max, but is there anything similar for TTYs? Or is it defined as a fixed value in kernel headers, I couldn't find that
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What is stored in /dev/pts files and can we open them?

According to my knowledge, /dev/pts files are created for ssh or telnet sessions.
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How does a Linux terminal work?

If you fire up a terminal and call an executable (assuming one thats line oriented for simplicity) you get a reply to the command from the executable. How does this get printed to you (the user) does ...