Bash script to replace part of file name

Suppose a folder has following files

abcde-l1.mp3 abcde-l2.mp3 abcde-l3.mp3 abcde.meta.xml abcde.wav

We want to rename them to

12345-l1.mp3 12345-l2.mp3 12345-l3.mp3 12345.meta.xml 12345.wav

 #!/bin/bash  
   
 if [[ ! $1 ]]; then  
   echo "No argument supplied"  
   exit 1  
 fi  
   
 newname=$1  
   
 for entry in /Users/msun/msun/sound/*.wav; do  
  #Get file name without path e.g. abc.wav  
  filename=$(basename $entry)  
  #Get file name without extension e.g. abc  
  filename="${filename%.*}"  
  break   
 done  
   
 #replace $filename with $newname  
 for entry in /Users/msun/msun/sound/*; do  
  mv $entry ${entry/$filename/$newname}  
 done