Setting up a Minecraft launcher on Ubuntu 12.04, these steps worked for me, mostly pieced together from the various other tips.
In a terminal, first fetch a Minecraft image icon:
cd /usr/share/icons; sudo wget http://images.wikia.com/yogbox/images/d/dd/Minecraft_Block.svg
Then create a minecraft.desktop file (using the gedit text editor to keep it user-friendly; just enter the whole "gksudo ..." command at the command line):
gksudo gedit /usr/share/applications/minecraft.desktop
and paste in these contents, and then Save of course:
[Desktop Entry]
Name=Minecraft
Comment=
Exec=/opt/minecraft.sh
Icon=Minecraft_Block
Terminal=false
Type=Application
StartupNotify=true
(Note: you can also paste directly into the file by using
sudo sh -c 'xsel -ob > /usr/share/applications/minecraft.desktop'
if you have xsel installed.)
Finally (almost), open up your file manager and go to /usr/share/applications - either click the Home Folder icon in your launcher and navigate, or here's the terminal quickie:
nautilus /usr/share/applications &
Locate your new Minecraft entry, and drag it over to your launcher bar.
At this point, you're practically done, except in this case I've created a little Minecraft starter script, saved in /opt/minecraft.sh, which assumes the minecraft.jar file is also saved in /opt. You can change all these "/opt" references to be wherever you've saved the original minecraft.jar file (be sure to change the Exec value in the minecraft.desktop file too).
The minecraft.sh file needs to contain just these three lines:
#!/bin/bash
cd $(dirname "$0")
java -Xmx1G -Xms512M -cp minecraft.jar net.minecraft.bootstrap.Bootstrap
(NOTE: for versions older than 1.6.1, you will need to use net.minecraft.LauncherFrame instead of net.minecraft.bootstrap.Bootstrap. The internal structure of the file and classes has changed as of 1.6.1.)
and of course that script needs to be executable, e.g. with the command
sudo chmod a+x /opt/minecraft.sh
If you have a system with more memory or notice poor performance when playing with higher render distances, you can increase the value of the -Xmx1G flag as desired. This tells Java the maximum amount of memory it's allowed to use. -Xmx1G means that it has a cap of 1 GB. -Xmx2G would be 2 GB, -Xmx3G would be 3 GB, and so on.
That's it! Using the starter script, and ensuring it cd's to the folder that contains the minecraft.jar file, seems to be a helpful step that other instructions overlooked.
Best Answer
It seems there exists no way to remove or disable “Unlock from launcher” in the Quicklist of a Launcher-Icon.
But I found a workaround that saves the current order of the icons in the Launcher and - in the case that an icon was mistakenly removed from the Launcher - restores the order after every start, reboot or login.
Step 1: Save the current order of the icons in the Launcher: Start Terminal (Ctrl+Alt+T) and enter the command
gsettings get com.canonical.Unity.Launcher favorites > starter.icons(this will save the order in the file starter.icons in your home-directory).Step 2: Create a script in your home-directory by means of the command
gedit ~/starter.icons_restore.shand type the following text:Save the file and close Gedit.
Step 3: Make the file executable by means of the command
chmod +x ~/starter.icons_restore.shStep 4: Make a new entry in the Startup Applications: Klick on the wheel in the top-right corner and chose Startup Applications... > Press Add > Name: Restore Launcher-Icons > Command:
/home/<YourUsername>/starter.icons_restore.shFrom now on after every start, reboot or login, the order of the icons in the launcher will be restored according the information in the file ~/starter.icons.
P.S: Instead of Step 4 you can also create a Desktop-Starter with the command
/home/<YourUsername>/starter.icons_restore.shPP.S: Good news: In the case you have manually edited the quicklist of a Launcher-Icon, the amendments will be preserved even if the icon is (mistakenly) removed. That means, after restoring, the quicklist still contains all amendments.