The following two Bash scripts will interactively prompt for user input to create or delete user accounts on Mac OS X 10.4.11. Use them at your own risk!

1. Create a user account

#!/bin/bash

# cf. Adding a User From the Command Line,
# http://developer.apple.com/documentation/Porting/Conceptual/PortingUnix/additionalfeatures/chapter_10_section_9.html

if [[ "$(/usr/bin/whoami)" != "root" ]]; then printf 'nMust be run as root!nn'; exit 1; fi

OPATH=$PATH
export PATH=/usr/bin:/usr/sbin:/bin:/sbin

OIFS=$IFS
export IFS=$' tn'

declare sudo=/usr/bin/sudo dscl=/usr/bin/dscl

printf "e[1mEnter first namee[m: "
read firstname

# no spaces in names
if [[ -z "$(printf -- "$firstname" | /usr/bin/grep -Eo "^[^[:space:]]+$")" ]]; then
   printf 'nUse a name without spaces! nPlease, try again!nn'
   exit 1
fi

# name must not begin with a number
if [[ -n "$(printf -- "$firstname" | /usr/bin/grep -E "^[[:digit:]]")" ]]; then
   printf 'nName must not begin with a number! nPlease, try again!nn'
   exit 1
fi


# make sure the user name is unique
new_user="$(/usr/bin/dscl . -search /Users name "$firstname" 2>/dev/null)"

if [[ -z "$new_user" ]]; then
  new_user="$firstname"               
else
  printf "nUser name already exists: $firstname nPlease, modify your name and try it againx21nn"       # cf. man ascii for x21
  exit 1
fi 


# make sure the user's primary group name is unique 
# note: the user's primary group name is also based on the first name!

new_group="$(/usr/bin/dscl . -search /Groups name "$firstname")"

if [[ -z "$new_group" ]]; then
  new_group="$firstname"             
else
  printf "nThe user's primary group name already exists: $firstnamex21 nPlease, try againx21nn"
  exit 1
fi 


# make sure there is no (file or) home directory of the same name already
if [[ -e "/Users/$new_user" ]]; then
  printf "nUser $new_user already exists at /Users/$new_userx21 nPlease, try againx21nn"
  exit 1
fi


# last name

printf "e[1mEnter last namee[m: "
read lastname

# no spaces in names
if [[ -z "$(printf -- "$lastname" | /usr/bin/grep -Eo "^[^[:space:]]+$")" ]]; then
   printf 'nUse a name without spaces! nPlease, try again!nn'
   exit 1
fi

# name must not begin with a number
if [[ -n "$(printf -- "$lastname" | /usr/bin/grep -E "^[[:digit:]]")" ]]; then
   printf 'nName must not begin with a number! nPlease, try again!nn'
   exit 1
fi


# enter password

printf "e[1mEnter passworde[m: "
stty_orig=$(/bin/stty -g) 
pass=''
blank='false'

while [[ "$blank" != "true" ]]; do

   /bin/stty -icanon -echo

   c=$(/bin/dd bs=6 count=1 2> /dev/null)

   # Check for a CR.
   if [[ -z "$(printf -- "$c" | /usr/bin/tr -d "rn")" ]]; then
      blank='true'
   else
      /bin/stty echo
      printf "*"
      pass="$pass$c"
      /bin/stty -echo
   fi
done

/bin/stty icanon echo
/bin/stty "$stty_orig"
passwd1="$pass"
printf "n"


# check minimum password length: 6
if [[ -z "$(printf -- "$passwd1" | /usr/bin/grep -Eo "^([[:alnum:]]|[[:punct:]]){6,}$")" ]]; then
   printf 'nUse at least 6 characters (alphanumeric, punctuational) for your password! nPlease, try again!nn'
   exit 1
fi


# confirm password

printf "e[1mConfirm passworde[m: "
stty_orig=$(/bin/stty -g) 
pass=''
blank='false'

while [[ "$blank" != "true" ]]; do

   /bin/stty -icanon -echo

   c=$(/bin/dd bs=6 count=1 2> /dev/null)

   # Check for a CR.
   if [[ -z "$(printf -- "$c" | /usr/bin/tr -d "rn")" ]]; then
      blank='true'
   else
      /bin/stty echo
      printf "*"
      pass="$pass$c"
      /bin/stty -echo
   fi
done

/bin/stty icanon echo
/bin/stty "$stty_orig"
passwd2="$pass"
printf "n"


if [[ "$passwd1" != "$passwd2" ]]; then
   printf 'nPasswords do not match. nPlease, try again!nn'
   exit 1
else
   printf 'nPassword confirmation was successful!nn'
fi



# get unique id numbers (uid, gid) that are greater than 500
unset -v i new_uid new_gid idvar
declare -i new_uid=0 new_gid=0 i=500 idvar=0

while [[ $idvar -eq 0 ]]; do 
   i=$[i+1]
   if [[ -z "$(/usr/bin/dscl . -search /Users uid $i)" ]] && [[ -z "$(/usr/bin/dscl . -search /Groups gid $i)" ]]; then
      new_uid=$i
      new_gid=$i
      idvar=1
      #break
   fi
done

if [[ $new_uid -eq 0 ]] || [[ $new_gid -eq 0 ]]; then printf 'Getting unique id numbers (uid, gid) failed!n'; exit 1; fi

# old version
# get unique id numbers (for uid, gid) by increasing the highest id number already in use by 1
#new_uid=$(($(/usr/bin/dscl . -list /Users uid | /usr/bin/awk '{print $NF;}' | /usr/bin/sort -n | /usr/bin/tail -n 1) + 1))
#new_gid=$(($(/usr/bin/dscl . -list /Groups gid | /usr/bin/awk '{print $NF;}' | /usr/bin/sort -n | /usr/bin/tail -n 1) + 1))

# make sure $new_uid and $new_gid are equal
#if [[ $new_uid -ne $new_gid ]]; then
#   if [[ $new_uid -gt $new_gid ]]; then new_gid="$new_uid"; else new_uid=$new_gid; fi
#fi



# check once again ...

if [[ $new_uid -eq $new_gid ]] && [[ "$new_user" == "$firstname" ]] && [[ "$new_group" == "$firstname" ]]; then

# create the user's primary group
$sudo /usr/sbin/dseditgroup -o create -r "$firstname $lastname" -i $new_gid "$new_group"
$sudo $dscl . -append "/Groups/$new_group" passwd "*"

$sudo $dscl . -create "/Users/$new_user"
$sudo $dscl . -append "/Users/$new_user" RealName "$firstname $lastname"
$sudo $dscl . -append "/Users/$new_user" NFSHomeDirectory "/Users/$new_user"
###$sudo $dscl . -append "/Users/$new_user" NFSHomeDirectory "/Local/Users/$new_user"
$sudo $dscl . -append "/Users/$new_user" UserShell /bin/bash   
$sudo $dscl . -append "/Users/$new_user" PrimaryGroupID $new_gid
$sudo $dscl . -append "/Users/$new_user" UniqueID $new_uid
$sudo $dscl . -append "/Users/$new_user" hint ""
$sudo $dscl . -append "/Users/$new_user" comment "user account "$firstname $lastname" created: $(/bin/date)"
$sudo $dscl . -append "/Users/$new_user" picture "/Library/User Pictures/Animals/Butterfly.tif"
$sudo $dscl . -append "/Users/$new_user" sharedDir Public
$sudo $dscl . -passwd "/Users/$new_user" "$passwd1"

# add some other properties that are usually set (Mac OS X 10.4)
$sudo $dscl . -append "/Users/$new_user" _shadow_passwd ""
$sudo $dscl . -append "/Users/$new_user" _writers_hint "$new_user"
$sudo $dscl . -append "/Users/$new_user" _writers_real_name "$new_user"

$sudo $dscl . -append "/Groups/$new_group" GroupMembership "$new_user"      # add new user to the user's primary group
#$sudo /usr/sbin/dseditgroup -o edit -a "$new_group" -t user "$new_user"

$sudo $dscl . -append /Groups/staff GroupMembership "$new_user"             # test: add new user to group staff

# add the new user to the admin group (Mac OS X 10.4)
# This should be part of a separate admin user account shell script or 
# at least require an additional user input prompt at the beginning!
#$sudo $dscl . -append /Groups/admin GroupMembership "$new_user"
#$sudo $dscl . -append /Groups/appserverusr GroupMembership "$new_user"
#$sudo $dscl . -append /Groups/appserveradm GroupMembership "$new_user"

# log out after running the script to see the new user account has been created
$sudo /usr/sbin/createhomedir -l -u "$new_user"

else

   printf "nConfiguration of user account: $firstname failedx21 nPlease, try againx21nn"
   exit 1

fi


printf "nUser account:  $firstname  successfully createdx21 nYou can now log in to your new user accountx21nn"

export IFS=$OIFS
export PATH=$OPATH

exit 0


#---------------------------


# test
dscl . list /Users
dscl . -read /Users/<firstname>

dscl . list /Groups
dscl . -read /Groups/<firstname>
dscl . list /Groups GroupMembership

2. Delete a user account

#!/bin/bash

# cf. http://www.macos.utah.edu/documentation/authentication/dscl.html

if [[ "$(/usr/bin/whoami)" != "root" ]]; then printf 'nMust be run as root!nn'; exit 1; fi

OPATH=$PATH
export PATH=/usr/bin:/usr/sbin:/bin:/sbin

OIFS=$IFS
export IFS=$' tn'

declare sudo=/usr/bin/sudo

printf "e[1mDelete user accounte[m: "
read user

if [[ -z "$user" ]]; then printf 'nNo user specified! Please, try again!nn'; exit 1; fi

# make sure the user exists
usertest="$(/usr/bin/dscl . -search /Users name "$user" 2>/dev/null)"

if [[ -z "$usertest" ]]; then printf "nUser does not exist: $usernn"; exit 1; fi 


# get user's group memberships
groups_of_user="$(/usr/bin/id -Gn $user)"

if [[ $? -eq 0 ]] && [[ -n "$(/usr/bin/dscl . -search /Groups GroupMembership "$user")" ]]; then 
   # delete the user's group memberships
   for group in $groups_of_user; do
      $sudo /usr/bin/dscl . -delete "/Groups/$group"  GroupMembership "$user"
      #$sudo /usr/sbin/dseditgroup -o edit -d "$user" -t user "$group"           
   done
fi


# delete the user's primary group
if [[ -n "$(/usr/bin/dscl . -search /Groups name "$user")" ]]; then
   $sudo /usr/sbin/dseditgroup -o delete "$user"
fi

# if the user's primary group has not been deleted ...
if [[ -n "$(/usr/bin/dscl . -search /Groups name "$user")" ]]; then
printf "
   e[1mWarninge[m:
   The group memberships of the user e[1m$usere[m have been deletedx21
   groups_of_user: $groups_of_user
   The user's primary group e[1m$usere[m, however, has not been deletedx21
   Please, try againx21
   Exiting ...n
"
  exit 1
fi


# find the GeneratedUID of the user and remove the password hash file 
# from /private/var/db/shadow/hash/<GeneratedUID>
# sudo ls -a /private/var/db/shadow/hash
# sudo ls -l /private/var/db/shadow/hash/<GeneratedUID>

guid="$(/usr/bin/dscl . -read "/Users/$user" GeneratedUID | /usr/bin/awk '{print $NF;}')"

if [[ -f "/private/var/db/shadow/hash/$guid" ]]; then
   $sudo /bin/rm -f /private/var/db/shadow/hash/$guid
fi


# delete the user
$sudo /usr/bin/dscl . -delete "/Users/$user"

# make a backup
if [[ -d "/Users/$user" ]]; then
   $sudo /usr/bin/ditto -rsrc -c -k "/Users/$user" "/Users/${user}-archive-$(/bin/date).zip"
fi

# remove the user's home directory
if [[ -d "/Users/$user" ]]; then
   $sudo /bin/rm -rf "/Users/$user"
fi

export IFS=$OIFS
export PATH=$OPATH

exit 0