Ubuntu issues.

For some reason after running apt-get upgrades, and maybe a few other things happened in between, on my installation of Kubuntu 15.04, KDE had stopped working the way it should. It started with a crash and the screen turned black. Visible was only the mouse cursor which I could move, and IM Contacts which I could move too. Unfortunately I was unable to start any other program from within it, there was no panel, nor could I Alt+F2 to open anything through a command.

After looking around, and installing a whole bunch of other Desktop Environments (DE) which for the most part had other issues I didn't like, I managed to fix it.

By removing everything in ~/.cache/ and ~/.kde/, you basically are cleaning up and starting fresh. A reboot and it worked for me.

Note: well, not completely, in between I also purged my kubuntu-desktop with apt-get purge kubuntu-desktop and reinstalled apt-get install --no-install-recommends kubuntu-desktop, but I question if this was necessary at all.

DISTRIB_ID=Ubuntu  
DISTRIB_RELEASE=15.04  
DISTRIB_CODENAME=vivid  
DISTRIB_DESCRIPTION="Ubuntu 15.04"  
NAME="Ubuntu"  
VERSION="15.04 (Vivid Vervet)"  
ID=ubuntu  
ID_LIKE=debian  
PRETTY_NAME="Ubuntu 15.04"  
VERSION_ID="15.04"  
HOME_URL="http://www.ubuntu.com/"  
SUPPORT_URL="http://help.ubuntu.com/"  
BUG_REPORT_URL="http://bugs.launchpad.net/ubuntu/"  

Ubuntu Unity Dash showing no applications:

http://askubuntu.com/questions/125843/dash-search-gives-no-result

Try wiping cache:

$ rm -rf ~/.cache

Try installing unity-lens-applications and unity-lens-files relog:

$ sudo apt-get install unity-lens-applications unity-lens-files

Irssi or Weechat shortcut for switching windows alt+# does not work in Unity/Gnome

Issue is gnome-terminal has shortcuts which use the same combination to switch between terminal tabs. By disabling these, your commands will pass through to irssi/weechat and they will work properly. Edit-> Preferences, navigate to shortcuts tab and locate Switch to Tab %d, [1~10]. Clicking on the shortcut and hitting backspace will disable the shortcut.