This is a text-only version of the following page on https://raymii.org:
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Title       : 	Remove unused Ubuntu kernels
Author      : 	Remy van Elst
Date        : 	28-10-2013
URL         : 	https://raymii.org/s/snippets/Remove_Old_Ubuntu_Kernels.html
Format      : 	Markdown/HTML
---



This one liner will help you remove unused Ubuntu kernels. Ubuntu does not
remove kernels when they install a new one, however the default /boot partition
is relatively small, about 100MB. So after 10 kernels, you can get No Space Left
On Device errors with apt-get upgrading. Then you can eitehr remove them
manually, or use this one liner to automatically remove them all.

    
    
    export KERNEL="$(uname -r | grep -Po '([0-9\.\-]*[0-9])?')"; dpkg --get-selections | grep -E "linux-(header|image).*" | grep -iw install | sort | grep -v "$KERNEL" | grep -v "lts" | sed 's/install//g' | xargs dpkg -P
    

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Here's the command by command explanation:

    
    
    export KERNEL="$(uname -r | grep -Po '([0-9\.\-]*[0-9])?')"
    

The first portion sets the current kernel number in a variable `KERNEL`. It only
takes the number, and greps out any additions like `-generic` or `-server`.

    
    
    dpkg --get-selections 
    

The second portion first prints out all available packages.

    
    
    grep -E "linux-(header|image).*"
    

The third portion greps for all packages with either `linux-header` or `linux-
image` in the name.

    
    
    grep -iw install
    

The fourth portion greps out only installed packages.

    
    
    sort
    

The fifth portion sorts the output.

    
    
    grep -v "$KERNEL" | grep -v "lts"
    

The sixth portion filters out the current kernel and the lts kernel package.
Removing those will cause problems.

    
    
    sed 's/install//g'
    

The seventh part strips off the `install` part.

    
    
    xargs dpkg -P
    

The last part actually removes the packages. `xargs` send all the package names
to `dpkg`. Then `dpkg -P` purges the packages. That means, removing them and
removing their configs.

   [1]: https://www.digitalocean.com/?refcode=7435ae6b8212

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