Bulk rename in sh

I had a directory of files like "really long name with spaces 14.jpg" that I wanted to rename to files like "14.jpg".

My solution was the following.

ls -d *jpg | sed 's/.* \([0-9]\+\.jpg\)/mv "\0" \1/' | sh

So I can decipher this later:

• The sed filter replaces the lines in the ls output with mv commands from original to stripped filename; these are then piped to sh.
• Parens and the Kleene plus must be escaped.
• sed uses basic regexp which isn't supposed to use Kleene plus but somehow it works. Adding -r for extended makes it complain.
• \0 expands to the entire matched string, \1 expands to the matched parenthesized group.