usermanagement

what information is contained in /etc/default/useradd

# cat /etc/default/useradd # useradd defaults file GROUP=100 HOME=/home INACTIVE=-1 EXPIRE= SHELL=/bin/bash SKEL=/etc/skel CREATE_MAIL_SPOOL=yes skell, bash shell and home directory and all are defined here. - Default permission of /etc/skel is drwxr-xr-x. - It is not recommended to change the permission of skel directory or its contents. Changing the permission may possibly break some of the program, because in skel directory there are some profiles that needs the permission of read and trying to give it permission of execute will cause some programs/profiles to work unexpectedly.

Verify that user vivek does not exists? verfify that a group developer does not exist

# grep "^vivek" /etc/passwd grep "^developers" /etc/group

How to add a new user to primary group using useradd you can do the same task using usermod

# useradd -g developers tony # id tony

This file defines the site-specific configuration for the shadow password suite

/etc/login.defs

what is purpose of skel directory

/etc/skel/ (skel is derived from the "skeleton") is used to initiate home directory when a user is first created. "skeleton" directory is defined in /etc/default/useradd file .bashrc .bash_profile -.bash_logout

how to change the passwd related information in linux

chage username chage [options] username chage vivek chage -l tom -m, --mindays MIN_DAYS set minimum number of days before password change to MIN_DAYS -M, --maxdays MAX_DAYS set maximim number of days before password change to MAX_DAYS or either change /etc/logindefs chage -M 30 z.abbas29

How do I verify integrity of password files?

pwck -r /etc/passwd pwck -r /etc/shadow pwck [options] /etc/shadow

how to add a new group in linux

sudo groupadd developers

How to add a existing user to existing group using usermod

usermod -a -G ftp tony

how to change the primary group for the user tony from www to tony

usermod -g www tony

difference between useradd vs usermod

Add a new user called jerry to secondary group named cartoons on Linux: sudo useradd -G cartoons jerry Add a new user called tom to primary group called cartoons: useradd -g cartoons tom Linux add a existing user named spike to existing group named cartoons: useradd -g cartoons spike if you need to perform any existing change related to existing group or existing user, you can use usermod command.

what are five most important files for usermanagement

All user account related information are stored in the following files: /etc/passwd - Contains one line for each user account. /etc/shadow - Contains the password information in encrypted formatfor the system's accounts and optional account aging information. /etc/group - Defines the groups on the system. /etc/default/useradd - This file contains a value for the default group, if none is specified by the useradd command. /etc/login.defs - This file defines the site-specific configuration for the shadow password suite stored in /etc/shadow file

how to restore user home directory

Copy all the files from /etc/skel directoy in user's home directory cp -r /etc/skel/* ~/ what files will be changed by doing so. There are 2 important files/directories which are required to restore the user's home directory to default. They are mainly: 1. /etc/skel direcory 2. /etc/default/useradd