To run a command as administrator (user "root"), use "sudo <command>".
See "man sudo_root" for details.
ubuntu@ubuntu:~$ lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
loop0 7:0 0 1.7G 1 loop /rofs
loop1 7:1 0 86.6M 1 loop /snap/core/4486
loop2 7:2 0 140M 1 loop /snap/gnome-3-26-1604/59
loop3 7:3 0 1.6M 1 loop /snap/gnome-calculator/154
loop4 7:4 0 12.2M 1 loop /snap/gnome-characters/69
loop5 7:5 0 21M 1 loop /snap/gnome-logs/25
loop6 7:6 0 3.3M 1 loop /snap/gnome-system-monitor/36
sda 8:0 0 111.8G 0 disk
├─sda1 8:1 0 499M 0 part
├─sda2 8:2 0 99M 0 part
├─sda3 8:3 0 16M 0 part
├─sda4 8:4 0 39.4G 0 part
└─sda5 8:5 0 71.8G 0 part
sdb 8:16 1 29.3G 0 disk
└─sdb1 8:17 1 29.3G 0 part /cdrom
sdc 8:32 1 7.2G 0 disk
ubuntu@ubuntu:~$ sudo fsck /dev/sdc1
fsck from util-linux 2.31.1
e2fsck 1.44.1 (24-Mar-2018)
fsck.ext2: No such file or directory while trying to open /dev/sdc1
Possibly non-existent device?
ubuntu@ubuntu:~$ sudo fsck /dev/sdc
fsck from util-linux 2.31.1
e2fsck 1.44.1 (24-Mar-2018)
ext2fs_open2: Bad magic number in super-block
fsck.ext2: Superblock invalid, trying backup blocks...
fsck.ext2: Bad magic number in super-block while trying to open /dev/sdc
The superblock could not be read or does not describe a valid ext2/ext3/ext4
filesystem. If the device is valid and it really contains an ext2/ext3/ext4
filesystem (and not swap or ufs or something else), then the superblock
is corrupt, and you might try running e2fsck with an alternate superblock:
e2fsck -b 8193 <device>
or
e2fsck -b 32768 <device>
[COLOR="#FF0000"]ubuntu@ubuntu:~$ sudo dd if=/dev/zero of=/dev/sdc
dd: writing to '/dev/sdc': Input/output error
24737+0 records in
24736+0 records out
12664832 bytes (13 MB, 12 MiB) copied, 501.017 s, 25.3 kB/s
[/COLOR]ubuntu@ubuntu:~$ sudo mkfs.msdos -f 32 /dev/sdc1
mkfs.fat 4.1 (2017-01-24)
Bad number of FATs : 32
Usage: mkfs.fat [-a][-A][-c][-C][-v][-I][-l bad-block-file][-b backup-boot-sector]
[-m boot-msg-file][-n volume-name][-i volume-id]
[-s sectors-per-cluster][-S logical-sector-size][-f number-of-FATs]
[-h hidden-sectors][-F fat-size][-r root-dir-entries][-R reserved-sectors]
[-M FAT-media-byte][-D drive_number]
[--invariant]
[--help]
/dev/name [blocks]
ubuntu@ubuntu:~$ sudo mkfs.msdos -f 32 /dev/sdc
mkfs.fat 4.1 (2017-01-24)
Bad number of FATs : 32
Usage: mkfs.fat [-a][-A][-c][-C][-v][-I][-l bad-block-file][-b backup-boot-sector]
[-m boot-msg-file][-n volume-name][-i volume-id]
[-s sectors-per-cluster][-S logical-sector-size][-f number-of-FATs]
[-h hidden-sectors][-F fat-size][-r root-dir-entries][-R reserved-sectors]
[-M FAT-media-byte][-D drive_number]
[--invariant]
[--help]
/dev/name [blocks]
ubuntu@ubuntu:~$ sudo mkfs.ext4 -f /dev/sdc1
mkfs.ext4: invalid option -- 'f'
Usage: mkfs.ext4 [-c|-l filename] [-b block-size] [-C cluster-size]
[-i bytes-per-inode] [-I inode-size] [-J journal-options]
[-G flex-group-size] [-N number-of-inodes] [-d root-directory]
[-m reserved-blocks-percentage] [-o creator-os]
[-g blocks-per-group] [-L volume-label] [-M last-mounted-directory]
[-O feature[,...]] [-r fs-revision] [-E extended-option[,...]]
[-t fs-type] [-T usage-type ] [-U UUID] [-e errors_behavior][-z undo_file]
[-jnqvDFSV] device [blocks-count]
ubuntu@ubuntu:~$ sudo mkfs.ntfs -f /dev/sdc
/dev/sdc is entire device, not just one partition.
Refusing to make a filesystem here!
ubuntu@ubuntu:~$ sudo mkfs.ntfs -f /dev/sdc1
Failed to access '/dev/sdc1': No such file or directory
The device doesn't exist; did you specify it correctly?
ubuntu@ubuntu:~$