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linux user and group exercises solutions

  • Find out what user are you currently logged in as
    • whoami
  • List all users
    • /etc/passwd
    • compgen -u
  • How to find who is logged in?
    • w
  • Create a user
    • adduser $NEW_USERNAME
  • How to delete a user
    • userdel $USER
    • uderdel --remove $USER
  • Get information about a user such as UID and GID
    • id $USER
  • What files store password information and how do they work?
  • Change default settings for a new user, where is the helper file?
    • /etc/default/useradd and /etc/login.defs
  • How to manage passwords?

    • TODO

      • How to set minimum password requirements
      • How to check what accounts have a password set
    • Get password information on specific user
      • chage -l $USER
    • Password flags
      • -n , number of days between password change
      • -w, set warning days
      • -x, Max number of days between password change
    • Password expires at certain date
  • How to manage user environments?
    • Where is the default home holder for new users?
      • /etc/skel
    • Where are user environments
      • /etc/profile
      • /etc/bashrc
      • ~/.profile
      • ~/.bashrc
  • Where can one find a list of all groups?
    • /etc/group
      • Group name
      • Group password
      • Group ID
      • Members
  • List all groups
    • getent group
  • Create a group
    • groupadd
  • How to delete a group?
    • groupdel $GROUP
  • How to add a user to a group?
    • usermod -aG $GROUP $USER
  • Change group that owns a file
    • groupmod
  • Add user to a group
    • RHEL usermod -aG $GROUP_NAME $USER
  • How to give sudo access
    • RHEL usermod -aG wheel $USER
  • Set default UID and password age?
    • page 122
    • /etc/default/useradd has some stuff
    • /etc/login.defs has what I am looking for