[SATLUG] Monitor res in Ubuntu 10.04
bruce.dubbs at gmail.com
Sun Jan 9 20:41:53 CST 2011
Robert Pearson wrote:
> [CLI (Command Line Interface) Tips & Tricks]
> As a general rule I always either use "sudo" in front of all commands
> or, for extended sessions, I do "sudo su -" for a "root" window any
> time I am working outside of my "echo $HOME" directory. "root" will
> then own all changes. If there is a conflict you can always "sudo" and
> change "root" ownership and permissions to individual ownership. I
> find this saves me a lot of grief and confusion.
As an aid, you may want to change ~/.bashrc for each user, including
root, to add:
if [[ $EUID == 0 ]] ; then
PS1="$RED\u$NORMAL@\h$RED [ $NORMAL\w$RED ]# $NORMAL"
PS1="\u$GREEN@\h$GREEN [ $NORMAL\w$GREEN ]\$ $NORMAL"
or some variation of that. It highlights the prompt when you are root
as a reminder.
> Ctrl-Alt-BackSpace - Will kill the X server process in an orderly
> fashion. This is a quick, easy, legitimate way to restart X. Note it
> does not restart the display manager (if used) -- just X itself.
For newer systems this is not set by default. You may need an xorg.conf
file to set it.
Option "DontZap" "No"
> Ctrl-Alt-Fx - where "x" corresponds to a valid tty number (typically
> 1-6). This is typically used to jump to a text console login, while X
> remains running. To get back to X, then it is "Alt-Fx". In this case,
> "x" represents one plus the last tty (e.g. Alt-F7 if there are six
> available ttys).
The number of consoles is normally 6, but you may want less in some
cases for security. For an sysvinit based system, it is set in
1:2345:respawn:/sbin/agetty tty1 9600
2:2345:respawn:/sbin/agetty tty2 9600
3:2345:respawn:/sbin/agetty tty3 9600
4:2345:respawn:/sbin/agetty tty4 9600
5:2345:respawn:/sbin/agetty tty5 9600
6:2345:respawn:/sbin/agetty tty6 9600
Just remove the lines you don't want. Your system may have a different
getty, e.g. mingetty.
On ubuntu, each virtual console is in a separate file: /etc/event.d/tty?
> [Does Logout restart X?]
> Re: Is a logout/login the same as restarting X?
Depends on the run level. Generally run level 5 will not restart X, but
restarts the graphical login manager. I prefer run level 3 which starts
at the command line. X is started with the startx command. In this
case, X is restarted upon logout and login.
> Logging out does not restart X. To restart X you have to
> ctrl+alt+backspace or "sudo killall gdm", for example. Conversely
> though, killing X will log out all users who have logged in through
> GDM. (gdm/GDM=Gnome Display Manager)
> [End Does Logout restart X]
> Both "Reboot (init 6)" and "Shutdown (init 0)" perform a "Logout"
> before stopping all the system processes.
> [A Really Interesting Use of X Display Managers]
> 3.2. Display Managers
> The other, more common, approach is the "GUI log-in", where X is
> running before log-in. This is done with the help of a "display
> manager", of which there are various implementations. XFree86 includes
> xdm (X Display Manager) for this purpose, though your distribution may
> use one of the others such as gdm (GNOME) or kdm (KDE).
> Display managers really do much more than enable GUI style log-ins.
> They are also used to manage local as well as remote "displays" on a
> network. We won't get into details on this here, but it is nicely
> covered in the Remote X Apps Mini HOWTO and the XDMCP HOWTO (see the
> links section). For our purposes here, they provide similar services
> to getty and login, which allow users to log into a system and start
> their default shell, but in a GUI environment.
Note that XDMCP is a security problem. A password goes on the network
unencrypted. I recommend ssh. If you need to run a graphical program
over ssh, that can be configured, but both the client and server need to
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