A representation of a device that asynchronously transmits and receives serial data.

learn more… | top users | synonyms

688
votes
5answers
161k views

What is the exact difference between a 'terminal', a 'shell', a 'tty' and a 'console'?

I think these terms almost refer to the same thing, when used loosely: terminal shell tty console What exactly does each of these terms refer to?
77
votes
2answers
62k views

Linux: Difference between /dev/console , /dev/tty and /dev/tty0

On a Linux system, what is the difference between /dev/console, /dev/tty and /dev/tty0? What is their respective use and how do they compare?
46
votes
2answers
48k views

Difference between pts and tty

Possible Duplicate: What is the exact difference between a 'terminal', a 'shell', a 'tty' and a 'console'? I always see pts and tty when I use the who ...
43
votes
2answers
5k views

Can a terminal emulator be as fast as TTY 1-6?

I've been trying various terminal emulators lately, from the built-in gnome-terminal, aterm, xterm, wterm, to rxvt. The test I've been doing is in this order: Open up a tmux window with 2 panes The ...
34
votes
4answers
5k views

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 ...
33
votes
1answer
1k views

What happens when Ctrl + Alt + F<Num> is pressed?

I am looking for an explanation of what happens in Linux when this key combination is pressed to change the current terminal. In particular, what software component intercepts this key combination and ...
32
votes
9answers
138k views

How to connect to a serial port as simple as using SSH?

Is there a way to connect to a serial terminal just as you would do with SSH? There must be a simpler way than tools such as Minicom, like this $ serial /dev/ttyS0 I know I can cat the output ...
26
votes
3answers
1k views

Do programs run from an ssh session depend on the connection?

Does a program that is run from an ssh session depend on the connection to the client? For example when the connection is really slow. So does it actively wait until things are printed on the screen? ...
21
votes
3answers
11k views

Start a process on a different tty

After about an hour of Googling this, I can't believe nobody has actually asked this question before... So I've got a script running on TTY1. How do I make that script launch some arbitrary program ...
19
votes
6answers
23k views

How can I hook on to one terminal's output from another terminal?

I need to hook onto output of currently running terminal (tty1) from virtual terminal and capture it (running X server). I'm pretty sure such a thing is possible by simpler means than debugging ...
18
votes
2answers
5k views

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 ...
17
votes
1answer
28k views

Is it okay to disable requiretty?

I'm trying to set up a deploy script using Capistrano At a step cap deploy:setup script is connecting to my server and trying to run commands that create directories. Then I see an error: msudo: ...
17
votes
5answers
5k views

Get ssh to forward signals

I want to be able to send signals (SIGINT is the most important) through ssh. This command: ssh server "sleep 1000;echo f" > foo will start sleep on server and after 1000 seconds it will put ...
16
votes
2answers
1k views

Can the empty spaces/background in a terminal be replaced with a random(but pretty) pattern of ASCII characters?

Context and Question There are many ways to colorize the terminal and shell environment. The output of individual commands, such as ls and grep, can also be colorized. Not directly related but ...
14
votes
7answers
15k views

How to stop cursor from blinking

How do I make the cursor stop blinking when in a TTY? (or anywhere else). BONUS Points for one universal setting that stops the cursor blinking almost everywhere.
14
votes
2answers
50k views

Can I change the font of terminal?

I have a Unix-like OS installed without desktop. Is it possible to change the font of the terminal?
13
votes
5answers
648 views

How to get the tty in which bash is running?

In the second method proposed by this page, one gets the tty in which bash is being run with the command: ps ax | grep $$ | awk '{ print $2 }' I though to myself that surely this is a bit lazy, ...
13
votes
1answer
2k views

Screenshot of X from tty

Using Xvfb I can launch an application and take a screenshot. What I'm wondering about is how to capture from an existing (dormant) X session. Say from tty or over ssh. From what I understand ...
12
votes
2answers
518 views

Possible to configure Login TTY over Audio device (Morse code or similar)?

One of the most miserable aspects of my day job is the need to occasionally investigate problems with machines scattered in remote locations all over the world that don't have network access to the ...
12
votes
1answer
3k views

What exactly is scrollback and scrollback buffer?

What are "scrollback" and "scrollback buffer" in programs like bash and screen, and how do they relate to the tty, the programs being run, and stdin/ stdout/ stderr? Here is the only definition of ...
12
votes
3answers
4k views

Rebinding/disabling CTRL+ALT+F#

I have an application that binds CTRL+ALT+F7, but my linux machine seems to catch the keystroke. Is there a way to rebind/disable this key? A recompile of the kernel is an acceptable answer. The ...
12
votes
1answer
5k views

TTY On External Monitor

When using my laptop at home, I usually use an external monitor, keyboard, and mouse with my laptop's screen as a second monitor. This is all easily configured using a nice GNOME utility that I ...
11
votes
2answers
264 views

Is there a way to mirror USB outputs?

I'm currently writing a program for a project. It is for a braille reading system where I have a braille display connected via USB that is controlled by a program called brltty. One of the ...
10
votes
3answers
1k views

Are there any linux terminals which can handle all key combinations?

I like to use emacs in terminal mode (-nw), but it seems most (all?) terminals can't handle some key combinations - for example, C-<RET> or C-M-%. I know this is because most terminals emulate a ...
10
votes
2answers
14k views

set baud speed for tty

How do I set the baud speed for a specific tty (in this case a serial port)? I tried using stty -F /dev/tty.iap ispeed 19200 But get the error Invalid argument for every speed I try (2400, 4800, ...
9
votes
3answers
7k views

Why does awk do full buffering when reading from a pipe

I'm reading from a serial port connected to a gps device sending nmea strings. A simplified invocation to illustrate my point: $ awk '{ print $0 }' /dev/ttyPSC9 ...
9
votes
2answers
7k views

How to close a tty

I've opened several ttys and I don't know the key combination to use to close a tty. I'm using Arch Linux.
9
votes
1answer
333 views

Make program in a pipe think it has tty

Test environment: $ mkdir testdir $ cd testdir $ echo | tee "file name" Now, ls will print file?name (under Ubuntu GNU bash, at least), while ls | cat will print file and name in separate lines. ...
9
votes
4answers
10k views

Why are my virtual consoles completely blank?

When I go from my graphical session to a virtual console by Ctrl + Alt + F i (with i in 1 - 7 and 9-12) I see a completely black screen. Only on F8 I see the GUI. Not even a blinking coursor on the ...
9
votes
1answer
11k views

How to find which serial port is in use?

The Question: I plugged in a device (i.e. GSM modem) through a serial port (a.k.a. RS-232), and I need to see with which file in /dev/ filesystem this device was tied up, to be able to communicate ...
8
votes
4answers
549 views

ls command operating differently depending on recipient

How does commands like ls know what its stdout is? It seems ls is operating different depending on what the target stdout is. For example if I do: ls /home/matt/tmp the result is: a.txt b.txt ...
8
votes
5answers
6k views

How can I run `watch` as a background job?

When I run: watch 'cmd >> output.txt' & the job gets suspended by the system: 3569 Stopped (tty output) Is there a workaround?
8
votes
2answers
2k views

Detect if running in a virtual terminal?

I'd like to autologin to tty1 on login and then use vlock to lock it. How can I detect from Bash if the current terminal is a console virtual terminal (e.g. tty1), so that I can put the vlock line ...
8
votes
1answer
2k views

In which cases is SIGHUP not sent to a job when you log out?

I read an answer from a user who claimed that running foo 2>&1 >& output.log & would result in foo continuing to run even when they log out. According to this user, this even ...
8
votes
1answer
10k views

How to change tty login prompt?

To be clear, I am not referring to /etc/issue (shown before the prompt) or /etc/motd (shown after login), but the prompt itself, which is currently hostname login: For good measure, I am running ...
8
votes
3answers
5k views

Show a notification across all running X displays

Using the command line, I'd like show a notification on every running X display. ( and running console ) Something like: notify-send-all 'Warning' 'Nuclear launch in 5 minutes, please evacuate' Is ...
8
votes
2answers
4k views

How do I permanently change the console TTY font type so it holds after reboot?

I'm running Ubuntu 15.04 64-bit Desktop Edition (A Debian based Linux). I used sudo dpkg-reconfigure console-setup from the command line to change the default console font type to Terminus. ...
8
votes
1answer
2k views

How do I use a font in .ttc format as the console font?

I rather dislike the available tty fonts and would rather use Menlo, which is what I use in OS X's Terminal. Menlo is in a .ttc format, but (from the contents of /usr/share/consolefonts) Linux seems ...
8
votes
1answer
526 views

What should interactive shells do in orphaned process groups?

(Re-posting in unix per the suggestion in http://stackoverflow.com/questions/13718394/what-should-interactive-shells-do-in-orphaned-process-groups) The short question is, what should a shell do if it ...
8
votes
4answers
9k views

Poor TTY resolution with nVidia driver

The resolution of the TTY1-6 is poor ~ 640×480 Ubuntu 11.10 | Grub2 | nVidia | NVIDIA GT215 Board I went through the process on this site and after the edit the GRUB menu appears in the correct ...
7
votes
3answers
2k views

Construct a command by putting a string into a tty

I managed to do this echo -n "command" > /dev/tty1 The letters appear, and the cursor moves, but they are "ghosts" – if you hit Enter, nothing happens (they are not in stdin). Edit: In the ...
7
votes
1answer
337 views

“w | tail” chops text at right margin (78 characters)

Summary: w | tail chops rows after 78th column. When I run the "w" command, it works as expected. However, when I pipe the output to "tail", it chops the output to 78 columns wide (truncates anything ...
7
votes
3answers
2k views

Create Null Modem Pair linux

I am looking to create virtual serial ports on Debian 6 squeeze. Basic requirements are: be able to connect as if port was a real serial port( IE be able to set baud, stop bits etc) com port pairs ...
7
votes
1answer
6k views

Read what is written to /dev/tty*

How can I read what is written to /dev/tty*(* = 0 - number of tty)? I tried sudo tail -f /dev/tty1 on one terminal(X) and then sudo cp .emacs /dev/tty1 from another. X didn't show the the content of ...
7
votes
1answer
807 views

bash: no job control in this shell

I have a minimal Linux system. init is /bin/bash, only bare minimum of libraries in /lib/, /dev/ is populated statically, no daemons running (no udev, ..) When bash starts, I get following error: ...
7
votes
1answer
101 views

Why does 8250 UART driver not wake up TTY if more than 256 characters are pending?

What is the motivation of this if-condition in void serial8250_tx_chars(struct uart_8250_port *up)? if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS) uart_write_wakeup(port); It has been ...
6
votes
6answers
2k views

Graphics in TTY

Something has come up which demands me to work only in command line. My primary job is programming (mostly in Fortran and Octave) and I need to display plots. As a lame example: I open octave and ...
6
votes
4answers
31k views

Pseudo-terminal will not be allocated because stdin is not a terminal

I'm trying to set up automatic SSH hopping through a server which doesn't have nc. This works from the command line: ssh -A gateway ssh steve@target (I have added my public key to the SSH agent). ...
6
votes
1answer
34k views

How to read/write to tty* device?

I have a device that sends information over USB to my computer. Arch Linux sets up this device by creating a file named ttyUSB0 in /dev/. I have been using GTKterm to receive this incoming information ...
6
votes
2answers
870 views

My process was killed but I cannot understand the kernel notice

I have a custom application running on an embedded x86 setup (built using buildroot and uClibc). The application has been running fine but this morning when I returned to work I discovered my process ...