1.How to mount unmount a disk ? First we can check disk partition fdisk -l or lsblk * we can create a directory where we want mount sudo mkdir /mnt/mydisk *we can use mount command to mount the disk sudo mount /dev/sdXn /mnt/mydisk *To unmount disk sudo umount /mnt/mydisk 2. How to unlock the username? *If a user account is locked due to multiple failed login attempts Then we can use below command sudo passwd -u username 3.How to set user to NO LOGIN *If we don't require interactive logins. Then we can use below command sudo usermod --shell /usr/sbin/nologin username The usermod command can be used to modify user account properties 4.what are the process states in linux The Linux process states are many *Running (R). : we are executing instructions on CPU *Sleeping(S) : Sleeping processes are not using CPU resources * Stopped (T). : A stopped process can be resumed or terminated. *Zombie (Z): : In an operating system ,processes that are terminated but , for