How to install VNC on Redhat and avoid getting "font catalog is not properly configured" error

 yum install -y  tigervnc-server tigervnc-server-module libXfont pixman xterm xorg-x11-twm

Fixing "authentication is required to set the network proxy ..." on Redhat/REL/OEL

Whenever i started  a vncsession i would get an popup window stating :

authentication is required to set the network proxy used for downloading packages.  An
application is attempting to perform an action that requires privileges.
Authentication as the super user is required to perform this action" and asking
for the root password.

I didn't have the root password for this machine and hitting cancel would just bring back the pop-up in a few minutes. After googling here is the best way i found to fix this problem:

From a terminal window run "gnome-session-properties" and un-check "PackageKit
Update Applet"

Finally restart your vncserver and the issue should be gone.

Fixing "Firefox is already running" error in Linux

If you are on Linux and you get the following error when trying to start Firefox, read on for a solution:

Firefox is already running, but is not responding. To open a new window, you must first close the existing Firefox process, or restart your system.

This error usually is not solvable with killing the Firefox process, since you won't find one in the list of the current processes.

So how do we get around it?

First, you need to go to your profile directory.

• cd  ~/.mozilla/firefox/[your_profile]

Then delete the following two files :

• rm lock
• rm .parentlock

You should be able to open Firefox now.

If you have this problem occurring often like me, put the above command in a shell script for more convenience.