/dev/sda1 /boot is full [duplicate]

/boot contains (among other things) the linux kernels you have installed. These come with updates every now and then.

Open a Terminal and type dpkg --list | grep linux-image and then hit ENTER

then compare the output from that with uname -r
... where the output tells which of the above you have in use.

All the others can be removed, freeing up space - unless you have a reason to keep them. That is accomplished by replacing "linux-image-x.x.x.x-generic" here:

sudo apt-get purge linux-image-x.x.x.x-generic

for each one that you wish to remove.

Then AFTER THE LAST - you MUST do this to clean up/recreate the boot menu accordingly

sudo update-initramfs -u                          # remakes boot ramdisk
sudo update-grub2                                 # re-creates boot menu

find /boot -type f -printf "%-16s %p\n" | sort -nr | head -n 20

... will show you the 20 largest files in /boot