I logged into the Gnome environment and my old desktop settings have changed or have some how been corrupted.
When I log in to the Gnome environment, I get a warning box that says I'm already logged in.
I have a large file that's too large to put in my networked "home" directory, such as an ISO image to be burned to a CD-R(W).
How do I mount/unmount CD-ROMs, DVDs, and floppy disks?
The X server seems to have crashed (I.e., there is no Red Hat login screen, just a command prompt).
The keyboard shortcuts seem to have changed. What are the new shortcuts?
I have existing source code, written in C++, that refuses to compile under Red Hat.
All of the LaTeX tools default to US Letter (8.5in x 11in) paper size.
I logged into the Gnome environment and my old desktop settings have changed or have some how been corrupted
Rename every directory in your home directory starting with '.gconf' or '.gnome' to a new name. (I.e., one would rename '.gnome2' to '.gnome2.bak'.). This will cause Gnome to rebuild its configuration data the next time you log in, giving you the default desktop.
When I log in to the Gnome environment, I get a warning box that says I'm already logged in
This could be one of several things. Usually, it means exactly what it says: you're logged into another computer somewhere else. You can still choose to log in, but your other login session may begin doing odd things. It's best to only be logged into one machine (graphically) at any given time. If you're not logged in anywhere else, it's safe to bypass the warning and log in. This is quite often caused by incorrectly exiting Gnome, by a machine crashing, or by logging out of one machine and into another before Gnome has had time to clean up the remnants of your last login session.
I have a large file that's too large to put in my "home" directory (such as an ISO image to be burned to a CD-R(W))
There are two locations on the Linux machines that can be used for temporary file space. Note the emphasis given to temporary,
as these two locations are cleaned out on a regular basis:
- /tmp (small in size, used by the system extensively, not recommended for use by non-system users)
-- Files are retained for only 10 days since they were last accessed - /var/tmp (large in size, available to all users)
-- Files are retained for 30 days since they were last accessed
How do I mount/unmount CD-ROMs, DVDs, and floppy disks?
The Gnome environment allows access to CD-ROMs, DVDs, and floppy disks by right-clicking anywhere on the desktop
and selecting the appropriate device type from the "Disks" sub-menu. Once the disk is mounted, an icon will appear
on the desktop and a check-mark will appear in the menu next to the disks you have mounted. To unmount the floppy disk, CD-ROM, or DVD,
follow the same procedure as you did to mount the disk. Clicking on a device in the "Disks" submenu that has a check-mark next to it
unmounts the disk (and ejects it in the case of CD-ROMs and DVDs.)
Under KDE, there may already be icons on your desktop for the floppy, CD-ROM, and DVD drives. If not, right click
anywhere on the desktop and select the device you want to use from the "Create New" menu. After the devices
icon appears on the desktop, the device can mounted and unmounted by right-clicking on the device's icon itself.
The X server seems to have crashed (I.e., there is no Red Hat login screen, just a command prompt).
This could be caused by a few different things, but the following are the most common:
- A user has switched to a virtual console, so the X server is running but is not being displayed to the monitor
- The X server has actually stopped running
The keyboard shortcuts seem to have changed. What are the new shortcuts?
| Desktop Environment | Keyboard Shortcut | Outcome of Shortcut |
|---|---|---|
| None | <ctrl>+<alt>+<F1-F7> | Switch between virtual consoles. (F7 is the default graphical console) |
| Gnome | <ctrl>+<alt>+<arrow keys> | Switch between virtual desktops |
| Gnome | <alt>+<tab> | Switch between applications within a virtual desktop. |
| KDE | <ctrl>+<tab> | Switch between virtual desktops |
| KDE | <alt>+<tab> | Switch between applications within a virtual desktop. |
I have existing source code, written in C++, that refuses to compile under Red Hat Enterprise Linux
Since version 3.0.0, GCC (the Gnu Compiler Collection) has been much more standards compliant, as well as
requiring code to be standards compliant. The most common "gotcha" can be found when compiling the following C++ code...
#include <iostream>
void main() {
cout << "Hello World\n";
}
When this seemingly simple and correct code is compiled using g++, the following is output.
% g++ helloworld.cxx -o helloworld helloworld.cxx: In function `int main()': helloworld.cxx:4: `cout' undeclared (first use this function) helloworld.cxx:4: (Each undeclared identifier is reported only once for each function it appears in.)
So, you've included "iostream" and it still says that "cout" is undeclared. The solution is to correctly use C++ namespaces. The following two techniques are both correct...
#include <iostream>
int main() {
std::cout << "Hello World\n";
return 0;
}
... or ...
#include <iostream>
int main() {
using namespace std;
cout << "Hello World\n";
return 0;
}
The important thing is to understand and use namespaces correctly. Contrary to standard belief, and according to the ANSI C++ standard, the "std" namespace is not to be consulted by default. GCC 3.x follows the ANSI standard for namespaces, thus causing all the confusion.
All of the LaTeX tools default to US Letter (8.5in x 11in) paper size.
Mathematical Sciences' Computer Advisory Committee have agreed that the default pagesize for common
LaTeX tools will be US Letter.
The tools directly affected are:
- pdflatex
- dvips
- xdvi
