Users Flashcards
Three types of accounts
root, standard user and service
command to edit the /etc/sudoers file, verifies for errors before commiting changes
visudo
check existing sudoers file for errors
visudo -c
check a sudoers file in a different location than the default
visudo -f {file location} -c
check sudoers file in strict mode, any aliases that are used before being defined will result in errors
visudo -s
output the sudoers file to a specified file in JSON format
visudo -x {filename}
command to create user accounts and configure basic settings (does not create a password)
useradd [options] [user name]
location where account is stored
/etc/passwd
a new account is configured according to options in this file
/etc/login.defs
Account home directory is populated with files from this directory
/etc/skel
useradd option for comment (usually used as field for user’s name)
-c
useradd option for expiration date
-e
useradd option set default shell
-s
useradd option view default config for new users
-D
command used to create a password for a new user created with useradd command
passwd
file that stores user account information
/etc/passwd
file owned by root that stores hashed password
/etc/shadow
command used to control password expiration, expiration warnings, inactive days and other info for existing accounts
chage [options] {user name}
change age
Set account to expire at specific date and time
chage -E 2022/12/31 brian
option to list password aging information
chage -l brian
option to set max days the password is valid
chage -M 90 brian
option to set min number of days until password can be changed
chage -m 1 brian
sets number of days before expiration that user will be warned to change their password
chage -W 5 brian
command used to modify settings for regular users (edits the /etc/passwd file)
usermod [options] {username}
modify comment field of user
usermod -c “User One” user1
modify account expiration date
usermod -e 2020/12/31 user1
add user to a group and keeps them in their existing groups
usermod -aG sales-group user1
modify a user’s login name
usermod -l user99 user1
two commands to lock a users account
passwd -l {user name}
usermod -L {user name}
two commands to unlock a users account
passwd -u {username}
usermod -U {user name}
command used to delete user accounts
userdel [options] {user names}
command to delete an account and remove the users home directory
userdel -r brian
