Rename A User's RealName Attribute if it exists from firstname to lastname

AccountRenameRealName.sh

#!/bin/bash

################################################################################
# This script will pull the provisionerID from the JumpCloud console and rename
# the specified user account to the matching username in JumpCloud. This script
# will not rename or remap the user's home directory.
################################################################################

# Variables

# User Account to Rename
UserToRename='firstname'
# Rename Account to:
AccountRename='firstname.lastname'

################################################################################
# Get Local Accounts on system and see if UserToRename exists
################################################################################
# Get the localAccounts on the system
localAccounts=$(dscl . list /Users UniqueID | awk '$2>500{print $1}' | grep -v super.admin | grep -v _jumpcloudserviceaccount)

if [[ ${localAccounts[*]} =~ $UserToRename ]]; then
    echo "Matched $UserToRename user found"
    selectedUser=$UserToRename
else
    echo "Trying case insensitive search..."
    selectedUser=$( echo "$localAccounts" | grep -i "\b$UserToRename\b")
fi

# If selectedUser is Null, exit
if [[ $selectedUser == "" ]]; then
    echo "Could not find user exiting... the following users exist:"
    echo "$localAccounts"
    exit 1
else
    echo "$selectedUser will be renamed"
fi

################################################################################
# Finally attempt to change the and realname attributes
################################################################################
dscl . -change /Users/${selectedUser} RecordName "${selectedUser}" "${AccountRename}"
testCommand=$(echo $?)
if [[ $testCommand != 0 ]]; then
    echo "Failed to make username changes"
    exit 1
else
    echo "User's Username: $selectedUser changed to $AccountRename"
fi