No space left on device under Ubuntu Linux

Today I had problems (“No space left on device” errors) during a system upgrade of Ubuntu Linux. There where error messages telling me the boot Partition is full: update-initramfs: Generating /boot/initrd.img-4.4.0-47-generic gzip: stdout: No space left on device That’s why I had to find out, whats in this boot folder. $> ls -al /boot -rw-r–r– […]