Newfs

When a partition is set up with disklabel and one wants to use this partition as a filesystem the filesystem must first be created. The newfs command does this.

To see what superblocks were written to an already newfs'd filesystem one can use newfs -N on OpenBSD: Warning: cylinder groups must have a multiple of 2 cylinders /dev/rwd0a:    2097648 sectors in 2081 cylinders of 16 tracks, 63 sectors 1024.2MB in 7 cyl groups (328 c/g, 161.44MB/g, 20608 i/g) super-block backups (for fsck -b #) at: 32, 330720, 661408, 992096, 1322784, 1653472, 1984160,
 * 1) newfs -N /dev/rwd0a

''This shouldn't wreck the filesystem, but just in case the author dump(8)'ed this filesystem in case this hypothesis was wrong. All good 5 minutes later, whew.''

In Linux the newfs command is called mkfs.