format sdb1

$ sudo mkfs -t ext4 /dev/sdb1
mke2fs 1.45.5 (07-Jan-2020)
/dev/sdb1 contains a ext4 file system
    last mounted on Fri Mar 24 10:56:30 2023
Proceed anyway? (y,N) y
/dev/sdb1 is mounted; will not make a filesystem here!
dhwan@dhwan-Aspire-A514:~$ sudo mkfs -t ext4 /dev/sdb1
mke2fs 1.45.5 (07-Jan-2020)
/dev/sdb1 contains a ext4 file system
    last mounted on Fri Mar 24 10:56:30 2023
Proceed anyway? (y,N) y
Discarding device blocks: done                            
Creating filesystem with 11727360 4k blocks and 2932736 inodes
Filesystem UUID: 18c120d2-3933-4e07-943b-e2d6b1c3c1d5
Superblock backups stored on blocks:
    32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208,
    4096000, 7962624, 11239424

Allocating group tables: done                            
Writing inode tables: done                            
Creating journal (65536 blocks): done
Writing superblocks and filesystem accounting information: done