They're not used at the same time but I can see the cause of the confusion.
- Metacity handles lightweight composting and also does window decorations.
- Compiz only does the window management garb and hands off window decoration to
gtk-window-decorator
or emerald
. By default gtk-window-decorator
is used to emulate the current Metacity theme but it also has its own cairo-based themes.
So while they might look similar in some aspects, apart from the actual theme files used, they're very different underlying code.
But why have both at all?
Because Compiz needs better hardware to run. Lots of people still don't have hardware that supports DRI, so Ubuntu includes both to give everybody a desktop.
When running a shell or most programs in a shell anything you type is echo'd back to the user's terminal by the kernel's tty subsystem. There's other special handling, too, for erase characters, Ctrl+R, Ctrl+Z, and so on.
Certain programs, (editors in particular) that run from a command line don't need or want this. For this reason they signal the kernel with an IOCTL call against the tty (terminal) device that they don't want this behaviour. They don't want special characters to do special things, either. Instead they ask the kernel for a "raw" mode. In particular, editor's like vim turn off various "echo settings". All this applies to real tty terminals on a computer's serial lines, or the virtual terminals at Alt+Ctrl+F4, or the really virtual terminals you get when you run something like gnome-terminal under a GUI.
Such programs are supposed to reset any modes they change on the virtual tty they are using before they quit, either by entering a quit editor command or by taking a signal (from Ctrl+C) for example.
If they fail to do this properly the tty is left in the funny state you have discovered. Since programs can fail to reset the terminal, the reset
command was written to allow the user to recover.
I assume the interrupt is messing with the python software you are running. I'd guess that that program isn't getting a chance to reset the terminal, or is simply failing to do so.
In the vim case, when I run your example I get the same behaviour you describe. I also see a message "Vim: Warning: Input is not from a terminal" (It goes away when you reset). This is because vim isn't started normally from the shell. Instead the 'grep
' and 'xargs
' commands have been using the standard input, normally occupied by the tty, for purposes of passing the file names from grep
tto xargs
.
In your posted output from stty -a
we can see "-echo", also confirming that this is the problem. If you were to kill vim in such a way that it couldn't handle the signal gracefully you would probably see the same problem.
The problem is described elsewhere at https://stackoverflow.com/questions/3852616/xargs-with-command-that-open-editor-leaves-shell-in-weird-state.
A solution for the vim case is avoid xargs and use instead:
vim $(grep foo * -l)
Here the list of files is constructed by the shell, as it had been by xargs, but the shell is calling vim, which is directly connected to the tty. There is warning message sent to the error output file, and vim sets and resets the tty settings correctly.
An alternative to reset
that doesn't clear the screen is stty sane
.
More references here, and another interesting one here. Another interesting solution is given in an answer to https://stackoverflow.com/questions/8228831/why-does-locate-filename-xargs-vim-cause-strange-terminal-behaviour.
Best Answer
Running
metacity --replace
does not make it run as a daemon. If you hit Ctrl-C or otherwise stop that metacity process from running (closing terminal would do that as well), you will be left without a window manager. That is why you lose your window decorations. I am not exactly sure why the keyboard stops functioning (my guess is that once the window manager is closed new updates to the window, like typing, won't be painted to the screen), but I have tested this and if you hit Ctrl+Alt+F1 you can still drop to the framebuffer. Clearly the keyboard has not stopped working entirely, in fact if you click a menu item ingnome-terminal
you can use the up and down arrows to navigate it.You should run metacity in a wrapper, such as
screen
, when you need to start it from terminal and then close the terminal window you used. Just runscreen metacity --replace
and press Ctrl+A+D to detach from thescreen
process.