Compact ext3/4 filesystems in a VM

compact-ext.sh

#!/bin/bash
# Compact ext3/4 filesystems in a VM
# Tools should all be available within a gparted live VM
# Enable discard support in VirtualBox with a command like:
# vboxmanage storageattach "GParted Live" --storagectl=VirtIO --port=0 --discard=on --nonrotational=on
# Or disable the fstrim and use
# vbox-img.exe compact --filename DISK.vdi
set -eux

for DEV in $(lsblk -o name,fstype --raw --paths | grep 'ext[34]' | cut '-d ' -f1)
do
  e2fsck -f -D -p "$DEV"
  resize2fs -M -p "$DEV"
  resize2fs -p "$DEV"
  zerofree -v "$DEV"
done

for DEV in $(lsblk -o name,fstype --raw --paths | grep 'ext[34]' | grep -v 0B | cut '-d ' -f1)
do
  mount "$DEV" /mnt
  fstrim -v /mnt
  umount /mnt
done