141 reputation
3
bio website
location Halifax, Canada
age 35
visits member for 1 year, 7 months
seen Aug 7 at 10:00
GNU/Linux hacker and command line junkie.

Aug
6
comment What is the difference between Terminal, Console, Shell, and Command Line?
Oops, I didn't have a recent kernel source lying around. CONFIG_TTY was only added in 2012. Anyway, yeah hopefully that helps anyone trying to wrap their head around what the different pieces of the puzzle are, and how they fit together.
Aug
5
revised What is the difference between Terminal, Console, Shell, and Command Line?
Separate the pty description from the shell paragraph. Also, had my terminology all screwed up for pseudo-terminals. They're called pseudo, not virtual, and I had master/slave reversed.
Aug
5
awarded  Editor
Aug
5
revised What is the difference between Terminal, Console, Shell, and Command Line?
incorporate the fruits of some discussion in comments. Thanks Gilles
Aug
5
comment What is the difference between Terminal, Console, Shell, and Command Line?
There is some symbiosis between the terminal emulator (or real terminal on a serial port), the kernel tty semantics/behaviour, and the shell or other process on the other end of the tty. I think I just half-convinced myself I'm wrong here: Consider resizing your xterm. "I resized my terminal" sounds to me more like it's talking about stty rows N cols M than just about changing the size of the X11 window. (although doing that will make xterm do the proper ioctls on the tty to update the terminal size parameters.)
Aug
5
awarded  Commentator
Aug
5
comment What is the difference between Terminal, Console, Shell, and Command Line?
hrm, yeah terminal does get used in that sense, too. With the assumption that there's a terminal emulator, or a serial port with a terminal appliance connected to it, on one end of the terminal device that the kernel is handling. The kernel tty handling (in cooked mode) only handles a few control codes (signals on ^c, line editting on ^u / ^? (delete). I'm trying to draw a line between the tty code and the part of Linux that implements a VT100-like terminal on a graphics card and a USB/ps2/AT keyboard. You can compile Linux without that, but not without tty.
Aug
5
comment What is the difference between Terminal, Console, Shell, and Command Line?
The xorg X server (strings /usr/bin/Xorg) doesn't use /dev/console to get hardware access. It does use /dev/tty0, and /dev/tty%d, and /dev/vc/%d, to set itself up on its own VT. I'm pretty sure Xorg would still run fine on a PC that booted with the kernel console on a serial port. And that the text-mode virtual terminals would still work. The more I consider this, the more I'm leaning towards viewing console in a kernel context as just a special terminal, selected at boot time. (Linux can actually output its console messages on multiple terminals at once, if you ask it to.)
Aug
5
comment What is the difference between Terminal, Console, Shell, and Command Line?
right, yes, echo foo | sudo tee /dev/console > /dev/null will print on the screen, if your current VT is in text mode (including framebuffer console, not just literally VGA textmode). If you booted with the console on a serial port, I think it would go there. You could say that /dev/console it the device file for whatever the kernel is treating as the system console. Nothing else in the system needs to have a notion of there being a console tty at all (except for boot-recovery stuff that starts a shell on the console TTY if the system fails to boot to multi-user mode. Usually from initrd)
Aug
5
comment What is the difference between Terminal, Console, Shell, and Command Line?
I'd have to disagree with you on terminal being a proper term for a terminal device file, and/or the terminal-handling code in the kernel (tty ioctls, raw/cooked, basic line editting). terminal = the stuff that handles escape codes, turns keypresses into characters, and draws on a screen (or prints on paper / tape). See my answer for more details.
Aug
5
awarded  Teacher
Aug
5
answered What is the difference between Terminal, Console, Shell, and Command Line?
Aug
5
comment Why is a virtual terminal “virtual”, and what/why/where is the “real” terminal?
virtual because the human input/output end of the terminal actually connects to a running process (through /dev/pts/*). Non-virtual terminals are things like the Linux text console (backend provided by kernel code to turn keystrokes into terminal input characters, and terminal output into characters on screen, including processing escape codes for color, cursor movement etc.). Or the oldest example of a non-virtual terminal, the serial ports. Terminal handling provided by whatever you hooked up to your serial port. You can boot with the text console on a serial port.
Aug
5
comment What is the difference between Terminal, Console, Shell, and Command Line?
@neon, they often go together, so people use one of the terms to refer to the collection. (i.e. it's usually obvious from context that they mean a terminal window providing an interface to a command line shell). Console is sometimes used as a synonym for terminal (KDE even has a terminal emulator called Konsole), but as 0xSheepdog points out, it also has another meaning: locally attached human-interaction hardware.
Jul
18
comment How do I resume a release upgrade/update?
do-release-upgrade does start a screen session (with screen escape character ^space), but if the parent do-release-upgrade process dies, that might still kill the whole thing. Be careful about hitting ^c if you start a subshell to poke at a modified conffile, I ran into a problem with that: bugs.launchpad.net/ubuntu/+source/ubuntu-release-upgrader/+bug/…
Oct
25
answered Get pulseaudio current sample rate and bit rate
Jun
9
answered How to solve apt “package cannot be configured because package is in a different version” errors?
Dec
27
comment growisofs fails with unable to O_EXCL /dev/scd0: someone was in time to remount?
update: actually some mounting and careful unmounting do appear to have solved it. /proc/<pid>/cwd doesn't show the working directory of a process still CDed to a force-unmounted filesystem, so I did find a shell that might have been CDed to a CD while I was trying to burn the first time
Dec
27
comment growisofs fails with unable to O_EXCL /dev/scd0: someone was in time to remount?
had this issue too, with 12.04 LTS, default desktop GUI setup (running from the livecd on a USB stick, actually). Hit the eject button on the drive to umount and open the tray,but now growisofs can't open /dev/sr0 with O_EXCL. I guess it didn't really unmount? But there's nothing about it still in /proc/mounts, and no processes with a cwd in /media or anything. I can mount and unmount burned discs with no complaints or effects on the problem. Is there a bug open for this on Launchpad?
Dec
27
comment How to avoid “Assuming drive cache: write through” message during restart?
Probably your system locked up during whatever it does next, after the step that printed the message about disk caches