olimex@a20-olinuxino:~$ sudo mkfs.ext4 /dev/sda1
mke2fs 1.44.5 (15-Dec-2018)
Discarding device blocks: done                            
Creating filesystem with 31258449 4k blocks and 7815168 inodes
Filesystem UUID: 31e2f011-36dd-4013-930e-02fa62333233
Superblock backups stored on blocks: 
	32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208, 
	4096000, 7962624, 11239424, 20480000, 23887872

Allocating group tables: done                            
Writing inode tables: done                            
Creating journal (131072 blocks): 
done
Writing superblocks and filesystem accounting information: done