a - fsck command fsck is used to verify the intergrity of a file system It checks for error( corrupted inodes, bad sectors, or broken file system structures) It can attempt to fix those errors before you check a filesystem you have to unmount it with umount sudo fsck -N /dev/sda → displays what it will do without doing anything sudo fsck /dev/sda → performs the check sudo fsck -n /dev/sda → perform a check but do not repair sudo fsck -f /dev/sda → forces a check -a → repairs errors automatically -v → verbose mode -t → test for bad sectors
b - mkfs command mkfs → Make File System mkfs is used to create and format file systems write sudo mkfs and use TAB key to show the supported filesystem types Create a file system on a partition sudo mkfs -t ext4 /dev/sda or sudo mkfs.ext4 /dev/sda Note that mkfs creates a new filesystem on existing partition or drive It does not resize or delete it. For this task you can use fdisk
c - dd command dd → Data description dd is used to copy and convert data from one place to another syntax → dd if=inputfile [bs=blocksize] [count=numcopies] Of=outputfile if → input file, where to read data from bs → sets the block size, default is 512 bytes (optional) count → specifies how many blocks will be transferred. All is default (optional) of → output file, where the data will be transferred to
d - dd command examples dd If=input.txt Of=backup.txt → copy a file dd If=/dev/sda bs=4M count=10240 of=image.img → create an image file from /dev/sda dd If=/dev/sda Of=/dev/sdc → clone a disk to another dd if=/dev/sda1 of=~/sda1partition.img → backup a partition dd if=sda1partition.img of=/dev/sda1 → restore the previous backup and if you need to create an CD-ROM ISO dd if=/dev/cdrom of=tgsservice.iso bs=2048