Goal : Create a bash script that can update itself

Example

./my-script.sh 
 $ Hello world

Then when supplied with argument to update itself

./my-script.sh --update

./my-script.sh
$ Hello World Updated!

Problem : Unable to update script while loaded in memory

Things I’ve tried

#!/bin/bash

function update {
 
 urlOfUpdatedVersion="..."
 existingScriptLocation = "..."
 myLocalPath="..."

 wget $urlOfUpdatedVersion > $myLocalPath/my-script.sh

 mv myLocalPath/my-script.sh $existingScriptLocation
}

if [[ "$1" == "--update" ]]; then
 update
fi

echo "Hello World"