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

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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 GPGGA,073651.000,6310.1043,N,...
6
votes
1answer
88 views

What does '?' represent under TTY

If you run ps in your terminal, you may see something like the following: What is ?? I'm ssh'ing into a Linux server, so I assume that it's just the sshd as it says under CMD, but I'm curious what ...
0
votes
0answers
11 views

Garbled font on tty1 (but not tty2-6) after booting

Running the latest OpenSUSE Tumbleweed, near the end of boot tty1's font gets completely scrambled (see the picture below). It's fine until shortly after mounting /, and the other ttys work just fine. ...
3
votes
0answers
33 views

slow file transfer through serial port with cat

I'm transferring a binary file to an embedded device using a custom AT command set. I'm running Lubuntu Linux on a virtual machine (Windows 7 host) and the virtual linux guest controls the physical ...
0
votes
2answers
61 views

Gap between two characters writing message over RS485

I am using an ATMEL embedded controller (at91sam9x25e) and its serial port to send/receive over RS485 Modbus RTU. Normal communication works fine, but sometimes - when writing - some packages are ...
1
vote
2answers
4k views

fsck problem when booting Debian stretch

I tried to boot my PC and I had this problem fsck from util-linux 2.26.2 /dev/sdb6 contains a file system with errors check forced. /dev/sdb6: Unconnected directory inode 1076721 (/var/tmp/???) /...
0
votes
0answers
27 views

Fresh Arch Installation - Terminal text completely unreadable just after boot

Update: Added additional text to identify which images are merely blurry, and which depict fubar text. My laptop is a Toshiba CB35-B3340. Also called a Chromebook 2, with part number PLM02U-009008. I ...
2
votes
3answers
2k views

Pasting binary data into a Unicode terminal

I need to be able to paste binary data into a terminal. For some reason, every byte outside the ASCII range (0x80-0xff) is pasted as the same three byte sequence 0xef 0xbf 0xbd. For example: $ echo -...
0
votes
0answers
2k views

TTY1 message help? (with picture)

When I boot up , I am greeted with a black TTY1 screen with the following error Kali GNU/Linux 1.0.7 kali tty (screenshot here) Kali Login:[ 31.695480] brcmsmac: bcma0:0: brcmsmac: ...
5
votes
2answers
1k views

How to open tty or execute some script when the shortcut Ctrl+Alt+F[1-6] doesn't work and X11 is partially frozen but system is still working?

I'm using Ubuntu 10.10 with Gnome on Acer Aspire One netbook. The X11 or just some parts of Gnome like panels and partially windows (details described below) are frozen which doesn't allow to do ...
8
votes
3answers
5k 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. ...
1
vote
1answer
22 views

Can't remove ttyS0 from /etc/securetty

Running RHEL6.6. Been trying to secure the system, and am having difficulty disabling root logins over the serial connection. My understanding is that I need to comment-out/remove the ttyS0 line, ...
2
votes
1answer
52 views

Strace output not showing system call

I am reading the source code of coreutils and I came to read tty.c code. Main function of tty is as follows: int main (int argc, char **argv) { char *tty; int optc; initialize_main (&argc, ...
0
votes
1answer
99 views

Accessing Console Of Ubuntu 16.04 KVM Guest

When I added Debian 8 to my KVM management tool, I found that I could not access the console unless I added console=ttyS0 to the grub boot configuration. It wasn't great but it worked. I am in the ...
3
votes
2answers
7k views

Run getty on a serial port on startup on RHEL

I want to put a getty on ttyS2 on a RHEL 6.1 box so I can use IPMI's serial-over-ethernet functionality to log in to a machine when SSH isn't working. In the past (on Ubuntu?), I used to add a line ...
4
votes
2answers
2k views

change tty login timeout - ArchLinux

By default when I login to my Arch linux box in a tty, there is a timeout after I type my username but before I type my password. So it goes like this Login: mylogin <enter> Password: (+ 60 ...
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 ...
27
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? ...
1
vote
0answers
21 views

MOZREPL output showing up in terminal window

I have a very a annoying problem. I've using Mac Terminal over SSH to write Perl script with vim on a local virtual Debian machine. The Perl script uses the WWW::Mechanize::Firefox module which in ...
4
votes
1answer
3k views

Why X server runs on TTY1 and not TTY7 on Arch Linux?

Edit: it seems Arch now uses TTY7 for X by default, so this question is irrelevant I've used Debian derivates (*buntu, CrunchBang), Mandriva, OpenSuSE, Fedora, name it.. all of them had X server at ...
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 "...
0
votes
2answers
42 views

tty, console prompt customization?

My Arch based system directly boots to tty and i never use x system or gui. I want to change prompt or whatever which looks like [root@0 ~]#. I want to change it to current time 12 hours format and no ...
2
votes
3answers
5k views

Endless data loop from dev/ttyUSB while sending AT commands

I have problem sending AT commands to my USB modem. At first I tried php-serial class, but when i was reading data, I got endless loop with strange data. Then I tried to debug problem and opened putty ...
4
votes
2answers
64 views

Tool to watch other ttys for linux?

BSD systems have a neat watch tool for snooping other ttys : Have you ever had a user login to your box and then ask you for help? Or have you ever been curious as to what your users are doing on ...
1
vote
1answer
81 views

How to get pinentry-curses to start on the correct tty?

I use gpg-agent for managing both PGP e SSH identities. The agent is started with a script like this gpg_agent_env="$XDG_CACHE_HOME/gpg-agent.env" export GPG_TTY="$(tty)" if ! ps -U "$USER" -o ...
1
vote
3answers
13k views

sudo: no tty present and no askpass program specified

I have a perl script that I fork from another script that I launch from a web browser via mod_perl. The forked script (which ends up running as apache) needs to sudo service X stop as part of a ...
2
votes
1answer
2k views

Setting up tty ports on Beaglebone Black with Angstrom linux

I'm using a Beaglebone Black running the Angstrom v2012.12 build that came pre-loaded. I want to be able to connect another device to a serial port via the UART connections on the GPIO headers. The ...
7
votes
1answer
122 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 ...
0
votes
1answer
90 views

Running SSH command from PHP gives sudo: no tty present and no askpass program specified error even though NOPASSWD settings are done

I am using LAMPP to run apache server. From a php file I am executing a python script which executes ssh, scp commands. But I am getting error: sudo: no tty present and no askpass program specified ...
1
vote
2answers
76 views

Why does SCP fail when “RequestTTY force” option is enabled?

In my SSH config file, I have to enable the RequestTTY force for some important reasons. And currently my config file looks like this: Host x.x.x.x HostName yyyy StrictHostKeyChecking no ...
1
vote
0answers
67 views

Unable to get login prompt on /dev/ttyUSB0

I am attempting to connect a TI-89 graphing calculator as a serial terminal to a Raspberry Pi running the latest version of Raspbian. The calculator is emulating a PL2303 serial adapter at /dev/...
1
vote
1answer
24 views

Find out if ctrl+backspace equals ctrl-H or ctrl-?

This question was about how to delete the last word in bash with ctrl-backspace. As already mentioned there, different Linux distros (or different Unices in general) behave differently: Some produce ^...
0
votes
1answer
330 views

Script to gracefully kill X server and drop to tty?

I use the terminal to do the majority of my day-to-day computing, so I have the default runlevel set to 3 in /etc/inittab and I only start the X server when I need to. I currently have the following ...
1
vote
0answers
34 views

Forward stdout to different tty

I have an external device, that I can send commands to, and it would respond in a certain way. For this I use two terminals, one sending the commands and one listening to the response. At some point I ...
0
votes
1answer
17 views

dmesg -n7 has no effect in virtual terminal

When I type dmesg -n7 in console (ie when I switch to tty1 using Ctrl+Alt+F1) I can see all debugging messages (new disks plugged in, etc). When I type dmesg -n7 in virtual terminal (terminal ...
9
votes
1answer
352 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. ...
6
votes
2answers
613 views

GNU Screen weird characters on click

I have a small problem in GNU screen. A GNU screen session runs on my RaspberryPi. Now sometimes, when I join it, if I click in the terminal (I'm using terminator on Fedora) I see weird characters ...
1
vote
1answer
46 views

Convert tty terminal output to plain text

I want to capture the text output of windows console app I run with wineconsole --backend=curses .... The app itself just uses boring stdio. Unfortunately, wine does a lot of escaping of the output, ...
10
votes
1answer
13k 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 ...
1
vote
1answer
21 views

Reserve pts range for some users

Is possible to reserve pseudo terminal range ids for some users ? Consider an user which should get preferable (or exclusively) pts id from 500 to 600, other from 0 to 400, and so on.
1
vote
1answer
35 views

Linux console can't display any language other than English while the terminal under Gnome can

I'm still new to Linux and Unix-like systems and I've tried to search on the internet about my issue. Unfortunately I don't get a feasible answer right now. My problem is that the console(tty) on my ...
3
votes
1answer
2k views

Ctrl-Alt-F1 not working from X

I have a system running Debian 5.0 that doesn't respond to Ctrl+Alt+F# (1-6) Check if Ctrl, Alt, F1 and F2 are intercepted correctly... $ DISPLAY=:0 xwininfo xwininfo: Please select the window ...
13
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 ...
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 ...
6
votes
9answers
5k views

Enabling Numeric Keypad

I have trouble with the numeric keypad (NumLock keys) being unusable while typing. While I don't think it's GUI specific, this happens both in Gnome and KDE. Sometimes it works in TTY, other times it ...
4
votes
1answer
855 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 ...
13
votes
5answers
702 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, ...
0
votes
1answer
24 views

If ALT+Fn is not handled by line discipline, is it handled by TTY driver?

The keystrokes mapped to signals in line discipline can be viewed by stty -e. The output is ALT+Fn keystroke is not in the list. So, is the keystroke handled by TTY driver? I read that line ...
0
votes
1answer
58 views

What part of TTY subsystem control the active /dev/ttyN (TTY device driver N)? [closed]

TTY subsystem contains TTY driver, line discipline and hardware drivers (keyboard driver, display driver). Let's say I use a virtual terminal/console. So, my current session uses /dev/tty1 (TTY driver ...
0
votes
0answers
61 views

No RC messages at the start between kernel loading and login prompt

I have a 4.3.2 kernel and OpenRC 0.19.1. After the kernel loads there is no messages from the RC scripts. And then, there is the prompt to log in. There is another system with identical rc.conf and ...