george314, you probably ran

george314, you probably ran the command without enclosing `uname -r` in single quotes.

"uname -r" is a command that tells you the version of the Linux kernel your computer is running. You can execute it independently. Give it a try.

The whole "sudo update-initramfs -u -k `uname -r`" is a bit more complex. Let's break it apart.

The first part, "sudo", is a command that will execute whatever follows it, with root privileges. This is necessary because you're going to make some changes to some important files, which could damage the whole system if done without care.

After the "sudo" command there is another command, the one that will be executed with root privileges: "update-initramfs". This one takes a few parameters.

The "-u" parameter tells "update-initramfs" to update an existing initrafms (the important files that are going to be changed).

The "-k" paramenter lets you determine which version of the file you want to change (you can have multiple Linux kernels installed on your machine, so you need to tell update-initramfs which one you want to change). Now this is the tricky part. You usually want to update the initramfs for the kernel your computer is running at the time, so you need to know exactly what version it is, which is not as simple as "2.6.22", because Linux distributions usually append other stuff to their kernels. So how do you know what to write there? Simple: you ask Linux to write it for you.

And that's what the `uname -r` part is for. This is yet another command that will be executed and its result will be passed on to the first command. It's a command that can take several parameters, depending on what you want it to tell you. In this case, you want the kernel version your computer is currently running, so you pass it the "-r" parameter. But in order for this command to be executed instead of interpreted as just some text you wrote yourself, you need to wrap it in single quotes. That's what tells the interpreter that there is something there that needs to be executed before the final command gets to run.

So, for instance, if you're running kernel "2.6.22-14-generic", which is the latest from Ubuntu, and you run "sudo update-initramfs -u -k `uname -r`" (without the double quotes, of course), this command will be parsed first and the `uname -r` command will be executed, resulting in "sudo update-initramfs -u -k 2.6.22-14-generic".

This is why you have to include the single quotes around `uname -r`. If you don't, "uname -r" will have no meaning for the interpreter and update-initramfs will have no idea which version it should update. Try to copy and paste the whole command from here.

Hope this helps.

PS - I removed your e-mail from your comment because of spammers.