Users and Groups Flashcards
What command shows basic information about a logged in user?
■ id
What ‘ps’ option shows processes with a terminal?
■ ‘a’
What ‘ps’ option shows the user associated with a process?
■ ‘u’
How does the operating system track users internally?
■ By UID number
What are the fields of an /etc/passwd entry?
■ username:password:UID:GID:GECOS:/home/dir:shell
■ username - mapping of UID to username
■ password - historical field for password now stored in /etc/shadow
■ UID - identifies the user at the most fundamental level
■ GID - user’s primary group ID number
■ GECOS - arbitrary text, usually user’s real name
■ /home/dir - location of user’s personal data and conf files
■ shell - program that provides the user’s command line prompt
Which group normally owns the files created by a user?
■ Primary Group
What command allows the user to log in to a new group changing the current real group ID to the named group?
■ newgrp
What command sets administers group membership and passwords?
■ gpasswd
Whats the difference between ‘su’ and ‘su -‘?
■ ‘su [username]’ starts a non-login shell as that user with the current environment
■ ‘su - [username]’ starts a login shell as that user with a new environment
Where are commands executed by ‘sudo’ logged?
■ /var/log/secure
Where are parameters for new accounts and groups kept?
■ /etc/login.defs
What command is used to configure user password time limits?
■ chage
What command is used to configure/administer user accounts?
■ usermod
What user account setting allows a user to login to a system but prevents interactive use?
■ nologin
What character in an /etc/shadow entry signifies a locked account?
■ !
When using the date and chage command to set password date limits, how must the date command be used?
■ chage -E date +%F -d +180days
■ The date command must be used with two date arguments to work. Once as the format wanted for the target command and then again for the forward date.
What daemon is responsible for retrieving and caching user information and authentication info?
■ sssd - system security services daemon
What tool is used to automate the configuration of SSO on Linux systems?
■ authconfig
What are the various tools included in the authconfig suite?
■ authconfig
■ authconfig-tui
■ authconfig-gtk (can be launched from system-config-authentication)
What tool is used to retrieve information about a network user?
■ getent
What specialized tool is used to enroll a client to an IPA server?
■ ipa-client-install
What tool is used to configure the host for connecting to a central LDAP server?
■ system-config-authentication
