create users and groups

# create linux group
groupadd pgradisys

 

# add user to group (primary)
useradd -g pgradisys kyfoo

# add user to group (secondary)
useradd -G pgradisys kyfoo

 

# modify user group (primary)
usermod -g pgradisys kyfoo

# modify user group (secondary)
usermod -G pgradisys kyfoo