user and group in linux

readme.md

add user to a group

sudo usermod -a -G groupname username

create the group if it doesn't exist:

groupadd -g 4200 sysadmin2

Next, create the user and add it to the group:

useradd sysadmin2 -u 4201 -g 4200 -m -s /bin/bash
useradd appadmin1 -u 4100 -g 4100 -m -s /bin/bash 

and don't forget to reset password for each user.