$ cat /etc/passwd

# cat /etc/shadow

$ cat /etc/group

• Использование библиотеки NSSWITCH

!!!! В ubuntu была замечана необходимость указывать shell !!!!

# useradd -u 10001 -m -s /bin/bash user1

# cat /etc/default/useradd

• bash

# passwd user1

#  echo user1:password1 | chpasswd

# apt install whois
$ mkpasswd -m sha-512

$ openssl passwd -1

# groupadd -g 15001 group1
# groupadd -g 15002 group2

# usermod -c "Ivan Ivanovitch Ivanov,RA7,401,499-239-45-23" user1

# usermod -G group1,group2 user1
или
# usermod -a -G group1 user1
# usermod -a -G group2 user1
или
# gpasswd -a user1 group1
# gpasswd -a user1 group2

# gpasswd -d user1 group1

# cat /etc/group
# getent group
# id user1

# cat /etc/shells

...
/usr/sbin/nologin
/usr/bin/passwd

# usermod -s /usr/bin/passwd user1

См. также chsh, chfn

server# usermod -d /home/zabbix zabbix

server# mkhomedir_helper zabbix

# man chage

# chage -l userX

# chage -E 2020-08-30 userX

• первый символ “!” в поле пароля

# passwd -l user1

# passwd -S user1

# passwd -u user1
  или, если надо разблокировать, но не задавать пароль
# usermod -p '*' root

# userdel -r student

$ sudo -s
...

# passwd
...

• How can I rename an unix user?

# usermod -l ivanovii -m -d /home/ivanovii user1

# groupmod -n ivanovii user1

• Move or migrate user accounts from old Linux server to a new Linux server

# ###export UGIDLIMIT=1000
# UGIDLIMIT=1001

# awk -v LIMIT=$UGIDLIMIT -F: '($3>=LIMIT) && ($3!=65534)' /etc/passwd >> /var/lib/lxc/www/rootfs/etc/passwd
# awk -v LIMIT=$UGIDLIMIT -F: '($3>=LIMIT) && ($3!=65534)' /etc/passwd | ssh www 'cat >> /etc/passwd'

# awk -v LIMIT=$UGIDLIMIT -F: '($3>=LIMIT) && ($3!=65534)' /etc/group >> /var/lib/lxc/www/rootfs/etc/group
# awk -v LIMIT=$UGIDLIMIT -F: '($3>=LIMIT) && ($3!=65534)' /etc/group | ssh www 'cat >> /etc/group'

# awk -v LIMIT=$UGIDLIMIT -F: '($3>=LIMIT) && ($3!=65534) {print $1}' /etc/passwd | tee - | egrep -f - /etc/shadow >> /var/lib/lxc/www/rootfs/etc/shadow
# awk -v LIMIT=$UGIDLIMIT -F: '($3>=LIMIT) && ($3!=65534) {print $1}' /etc/passwd | tee - | egrep -f - /etc/shadow | ssh www 'cat >> /etc/shadow'

# cd /home; tar -cf - . | (cd /var/lib/lxc/www/rootfs/home; tar -xvf -)
# cd /home; tar -cf - . | ssh www '(cd /home; tar -xvf -)'

# cd /var/mail; tar -cf - . | (cd /var/lib/lxc/www/rootfs/var/mail; tar -xvf -)
# cd /var/mail; tar -cf - . | ssh www '(cd /var/mail; tar -xvf -)'

groupadd -g 15001 group1

useradd -u 10001 -m -s /bin/bash -c "Ivan Ivanovitch Ivanov,RA7,401,499-239-45-23" -G group1 user1

useradd -u 10002 -m -s /bin/bash -c "Petr Petrovitch Petrov,RA7,402,499-323-55-53" -G group1 user2

useradd -u 10003 -m -s /bin/bash -c "Сидор Сидорович Сидоров,РА7,403,499-323-55-53" -G group1 user3

echo 'user1:password1' | chpasswd
   
echo 'user2:password2' | chpasswd

echo 'user3:password3' | chpasswd