User Manipulation Commands Syntax

adduser
script to create an new user interactively (slackware) or link to useradd (Redhat).

useradd, userdel, usermod
create, delete, modify an new user or update default new user information..

newusers
update and create new users (batch mode).

groupadd, groupdel, groupmod
add, delete or modify group.

chage. chfn, chsh
modify account policy (password length, expire data etc.) or finger information (full
name, phone number etc.) change default login shell.

linux init=/bin/sh rw
gain root access during boot prompt without password, can be used to fix some problems.
mount –w -n –o remount /

makebootdisk
make a bootable floppy disk