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mke2fs

Make ext[234] partitions.

Consider using gparted if you have X11.

Erase everything in a disk and create a single ext4 partition on it

First we must destroy the partition table, and create a single partition.

Only then we can use mke2fs on the partition (/dev/sdXY).

You should not use mke2fs on the disk device directly (/dev/sdX).

dev='/dev/sdX'
sudo umount "$dev"
printf "o\nn\np\n1\n\n\nw\n" | sudo fdisk "$dev"
sudo mkfs.ext4 "${dev}1"
mkdir -p d
sudo mount "${dev}1" d
ld d

Create partition in a regular file

Great way to study how file systems work byte by byte.

ext2 needs at least 64k (TODO exact minimum?)

F=a.ex2
dd if=/dev/zero of="$F" bs=1024 count=64
echo y | mke2fs -t ext2 "$F"
mkdir -p d
sudo mount "$F" d -o loop
# Do stuff
echo a > d/f
sudo umount d

Now file a.ex2 says:

a.ex2: Linux rev 1.0 ext2 filesystem data, UUID=f2c40840-cf93-49d9-a3b7-353c8994ee46

Command line options

  • -t: type: ext2, ext3, ext4
  • -L: label
  • -i: inodes per group (power of 2)
  • -j: use ext3 journaling. TODO for -t ext3/4, is it created by default?

mkfs.ext3

mkfs.ext4

Symlinks to mke2fs.

man mke2fs says it is the same as using -t ext4? mke2fs is able to differentiate them from args[0], much like BusyBox I guess.

mkfs.ext4dev

TODO? Vs mkfs.ext4?