A pty is a pseudo-terminal - it's a software implementation that appears to the attached program like a terminal, but instead of communicating directly with a "real" terminal, it transfers the input and output to another program.
Questions tagged [pty]
420 questions
8
votes
2 answers
Running vi from within haskell program (dealing with ptys)
I'm trying to write a logging shell; e.g. one that captures data about commands that are being run in a structured format. To do this, I'm using readline to read in commands and then executing them in a subshell whilst capturing things such as the…
Impredicative
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8
votes
2 answers
-serial pty in qemu, how to open?
I am running qemu with
-serial pty
option, and qemu gave this message
char device redirected to /dev/pts/1
however, it doesn't generate new window, I can do cat on pts1 from different window,
but then I can't input any character to it.
Is there…
Isa A
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8
votes
4 answers
Using subprocess with select and pty hangs when capturing output
I'm trying to write a python program that is able to interact with other programs. That means sending stdin and receiving stdout data. I cannot use pexpect (although it definitely inspired some of the design). The process I'm using right now is…
ravenac95
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7
votes
2 answers
Troubleshooting OSError: out of pty devices
From time to time I'm getting an OSError exception with the message 'out of pty devices' when calling pty.openpty() (it's happening when a bunch of instances of my scripts run concurrently).
What is the limit that I'm hitting? How can I get around…
kdt
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7
votes
1 answer
Pty doesn't get closed, althoguh close() syscall is called
I'm implementing features of an ssh server, so given a shell request I open a pty-tty pair.
A snippet:
import (
"github.com/creack/pty"
...
)
func attachPty(channel ssh.Channel, shell *exec.Cmd) {
mypty, err := pty.Start(shell)
go…
Noam Solovechick
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7
votes
1 answer
Python pty.spawn stdin not echoed but redirected to master's stdout
I want to call a program from Python and make it believe that its stdout is a tty even when Python's process stdout is attached to a pipe. So I used the pty.spawn function to achieve that, which can be verified from the following :
$ python -c…
Abhishek Kedia
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7
votes
0 answers
tcgetpgrp returns 0 -- implications?
Context:
I'm working on an application that needs to determine whether the
pseudo-terminal opened by a process is its controlling terminal. I'm trying to
use the tcgetpgrp() libc/system call to achieve this.
Observations:
1) I noticed that…
userRG
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7
votes
7 answers
How can I spy on communication between a process and a terminal?
I have a Linux process developed by a third-party that communicates with a terminal. For debugging I want to see the communication going back in forth.
One might think cat would do the trick (to see one direction):
./third-party-app &
cat…
jbarlow
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7
votes
3 answers
segmentation fault on pseudo terminal
I get a segmentation fault with this code on fprintf:
#define _GNU_SOURCE
#include
#include
#include
#include
#include
#include
#include
#include
#include…
muebau
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7
votes
1 answer
When pty [Pseudo terminal] slave fd settings are changed by "tcsetattr" , how can the master end capture this event without delay?
The slave fd is used by another application (say "A") as a serial port device .
A will set its baud rate/stop bit etc. My app needs this information .
BTW, is there any way for a process that has only the master fd open to be notified of all…
Shazoo
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7
votes
1 answer
Why does OpenSSH RequestTTY cause stderr redirected to stdout?
When running the same ssh command with -T and -t, any stderr output arrives on stderr vs. stdout, respectively.
No pty allocated:
ssh -T user@host "echo >&2 foo" 1>/tmp/out 2>/tmp/err
Output is written to /tmp/err.
With pty allocation: ssh -t…
gabor
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7
votes
1 answer
How do I set the terminal foreground process group for a process I'm running under a pty?
I've written a simple wrapper script for repeating commands when they fail called retry.py. However as I want to see the output of child command I've had to pull some pty tricks. This works OK for programs like rsync but others like scp apply…
stsquad
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6
votes
1 answer
How does `SIGWINCH` pass through Bash?
If I run a program in Bash that listens for SIGWINCH, and I resize the terminal that Bash is running in, then the program will receive SIGWINCH. I would like to know how this signal gets relayed to the program running under Bash.
Here is my…
Sean Kelleher
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6
votes
3 answers
Socat pseudo terminal: Can you make use of data lines (DTR, RTS etc)?
I'm creating a virtual serial port using socat.
socat -d -d pty,echo=0,raw pty,echo=0,raw
That works as expected so far. Using echo/cat I can send/receice text etc.
But what about signal lines like DTR or RTS? How would I get / set the state of…
Forivin
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6
votes
1 answer
Golang reading from stdin, how to detect special keys (enter, backspace... etc)
I have the following program that reads user input from stdin:
var input string = ""
exec.Command("stty", "-F", "/dev/tty", "cbreak", "min", "1").Run()
exec.Command("stty", "-F", "/dev/tty", "-echo").Run()
var b…
George H
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