Can’t install any package

I have xubuntu 18.04.3, and whenever I try to install a package through apt-get I get the following message: Removing linux-image-5.0.0-31-generic (5.0.0-31.33~18.04.1) … /etc/kernel/postrm.d/initramfs-tools: update-initramfs: Deleting /boot/initrd.img-5.0.0-31-generic /etc/kernel/postrm.d/zz-update-grub: Sourcing file `/etc/default/grub’ /usr/sbin/grub-mkconfig: 35: /etc/default/grub: FROM:: not found run-parts: /etc/kernel/postrm.d/zz-update-grub exited with return code 127 dpkg: error processing package linux-image-5.0.0-31-generic (–remove): installed linux-image-5.0.0-31-generic package post-removal script…

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