How to set up an filesystem

How to set up an encrypted filesystem

#fdisk -l /dev/sda
n
e
3
enter
enter

n
l
enter
+200M
p
w
#partprobe -a /dev/sda
#mkfs.ext3 /dev/sda4
#mkdir /data
#mount /dev/sda4 /data
#vim /etc/fstab
/dev/sda4 /data ext3 defaults 0 0
#mount -a
#mount | grep data