users

Modify user and groups 

user* {{{1

useradd, usermod, userdel, groupdel
	low level, more control

useradd [-G group] name
	Create new user + home dir

	--btrfs-subvolume-home [-i basedir] [-m to create dir needed on Debian?]
		create user home dir as a btrfs subvolum
		basedir defaults to /home



gpasswd
    may be safer alt to usermod because can change only one group at a time
	-a <username> <groupname>  
	-a sammy wheel

getend password
	show user passwd file entry

groups {{{1

usermod -aG <comma sep groupnames> user
	append group to existing

groupadd, groupmod 

getent group 
    show groups and members


shell {{{1

usermod -s <shell path>
    change shell

lchsh $USER

Other utils {{{1

adduser 
	high level tool, depends on perl
 	package shadow-utils
	Ubuntu: installed by default
	Fedora: adduser is symlink to useradd


	adduser -g wheel -m andmalc

	adduser <username> <groupname>
	add user to group <groupname>
	addgroup



Display & Change Groups (old) {{{1

id [user] - see info page
	id -nG  = print user's groups with names (no ids) - same as groups cmd.
	newgrp, sg
		change effect group ID.  Should be member of group to change to.
		See man pages for differences

PAM
	read Debian docs in libpam-doc package


Usergroup writable directories
	add users to group
	set group-id permission on dir
	users have umask 002

Umask
	subtracts permissions
	set in /etc/login.defs
		e.g.
		files
			umask 022 on files:
			default file rw-rw-rw- (666)
			umask (----w--w-)	(022)
			renders rw-r--r--	(644)
		dirs
			default directory permissions 777
			umask 022
			777-022=755	rwxr-xr-x