bash - How can I batch rename a set of filenames in Linux?

I have a folder with images named:

pic001-2.png
pic002-2.png
pic003-2.png 

How do I rename them to the following?

pic001.png
pic002.png
pic003.png 

I have tried mv "pic*-2.png" "pic*.png" but keep getting errors.

Answer

This will delete the first -2 found in each filename:

for f in pic*-2.png; do
  mv "$f" "${f/-2/}"
done

To test it, just prepend echo to the mv line.