/etc/useradd [-c comment] [-d directory] [-g group] [-G group1,group2,...]
[-m] [-s shell] [-u uid [-o]] [-x "extendedOptionString"] [-X optionsFile]
[hostname:]user
/etc/userdel [-x "extendedOptionString"] [-X optionsFile] [hostname:]user
/etc/usermod -D [-g group_name] [-s shell] [-x "extendedOptionString"]
[-X optionsFile]
/etc/usermod [-c comment] [-d directory [-m]] [-g group]
[-G group1,group2,...] [-l newname] [-s shell] [-u uid [-o]]
[-x " extendedOptionString"] [-X optionsFile] [hostname:]user