mkfs.ext4: add page (#3986)

pages/linux/mkfs.ext4.md

@@ -0,0 +1,11 @@
+# mkfs.ext4
+
+> Creates an ext4 filesystem inside a partition.
+
+- Create an ext4 filesystem inside partition 1 on device b (`sdb1`):
+
+`sudo mkfs.ext4 {{/dev/sdb1}}`
+
+- Create an ext4 filesystem with a volume-label:
+
+`sudo mkfs.ext4 -L {{volume_label}} {{/dev/sdb1}}`