Shell Script Changing Host Name.

hostnamechanger.sh

#!/bin/bash
# ------------------------------------------------------------------
# [Author] Title
#          Description
# ------------------------------------------------------------------

SUBJECT=some-unique-id
VERSION=0.1.0
USAGE="Usage: command -hv args"

# --- Option processing --------------------------------------------
while getopts ":vh" optname
  do
    case "$optname" in
      "v")
        echo "Version $VERSION"
        exit 0;
        ;;
      "h")
        echo $USAGE
        exit 0;
        ;;
      "?")
        echo "Unknown option $OPTARG"
        exit 0;
        ;;
      ":")
        echo "No argument value for option $OPTARG"
        exit 0;
        ;;
      *)
        echo "Unknown error while processing options"
        exit 0;
        ;;
    esac
  done

shift $(($OPTIND - 1))

param=$1
command="command"

# -----------------------------------------------------------------
LOCK_FILE=/tmp/${SUBJECT}.lock

if [ -f "$LOCK_FILE" ]; then
echo "Script is already running"
exit
fi

# -----------------------------------------------------------------
trap "rm -f $LOCK_FILE" EXIT
touch $LOCK_FILE 

# -----------------------------------------------------------------
function command {
    echo Current Local Host Name: `scutil --get LocalHostName`
    echo Current Computer Name: `scutil --get ComputerName`
    echo Current Host Name: `scutil --get HostName`

    sudo scutil --set ComputerName $param
    sudo scutil --set LocalHostName $param

    echo Changed Local Host Name: `scutil --get LocalHostName`
    echo Changed Computer Name: `scutil --get ComputerName`
    echo Changed Host Name: `scutil --get HostName`
}

# -----------------------------------------------------------------
# -----------------------------------------------------------------
if [ -n "$(type -t ${command})" ] && [ "$(type -t ${command})" = function ]; then 
   ${command}
else 
   echo "'${cmd}' is NOT a command"; 
fi