adduser.sh

#!/bin/bash

echo "Enter your desired user name: "
read USERNAME

echo "Enter a full name for this user: "
read FULLNAME

echo "Enter a password for this user: "
read -s PASSWORD

echo "Is this an administrative user? (y/n)"
read GROUP_ADD

if [ "$GROUP_ADD" = n ] ; then
    SECONDARY_GROUPS="staff"  # for a non-admin user
elif [ "$GROUP_ADD" = y ] ; then
    SECONDARY_GROUPS="admin _lpadmin _appserveradm _appserverusr" # for an admin user
else
    echo "You did not make a valid selection!"
fi

if  $UID -ne 0 ; then echo "Please run $0 as root." && exit 1; fi

MAXID=$(dscl . -list /Users UniqueID | awk '{print $2}' | sort -ug | tail -1)
USERID=$((MAXID+1))

echo "Creating necessary files..."

dscl . -create /Users/$USERNAME
dscl . -create /Users/$USERNAME UserShell /bin/bash
dscl . -create /Users/$USERNAME RealName "$FULLNAME"
dscl . -create /Users/$USERNAME UniqueID "$USERID"
dscl . -create /Users/$USERNAME PrimaryGroupID 20
dscl . -create /Users/$USERNAME NFSHomeDirectory /Users/$USERNAME
dscl . -passwd /Users/$USERNAME $PASSWORD

echo "Adding user to specified groups..."

for GROUP in $SECONDARY_GROUPS ; do
    dseditgroup -o edit -t user -a $USERNAME $GROUP
done

echo "Creating home directory..."
createhomedir -c 2>&1 | grep -v "shell-init"

echo "Created user #$USERID: $USERNAME ($FULLNAME)"