1) Select all of the files that you want to rename.

TIP: You can either click and drag you cursor over all of the files if they are grouped together or you can hold the command key and click each file individually.

2) Right-click (secondary click) one of the files and choose the rename option.

3) Make your desired changes to the names based on the following three options. Then, click Rename.

Replace Text

Replace some text in a file's name with different text.

Add Text

Add text to the beginning or the end of the file name.

Format

Format all file names with either a leading or trailing text for identifing large groups of sequential files.

This option being the most powerful, you have three options, Name and Index, Name and Counter, or Name and Date. All three have the name common, let you specify a string number from which to count up. "Index" uses the number alone, whereas "Counter" pads the number with zeros. "Date" adds the current date and time to the base file name.

TIP: Press command-z (⌘+Z) to undo any changes that you made.

Outcome

You have successfully bulk renamed your files.